Compositions and articles of manufacture containing branched polycarbonate

ABSTRACT

A polycarbonate containing composition comprising a peak melt viscosity of at least 8,000 poise when measured using a parallel plate melt rheology test at a heating rate of 10° C./min at a temperature of between about 350° C. to about 450° C., and wherein a molded article of the composition has a UL 94 V0 rating at a thickness of 1.0 mm, 1.5 mm, 2.0 mm, or between 1.0 mm and 2.0 mm is disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/913,906, filed Jun. 10, 2013, which is a continuation of U.S. patentapplication Ser. No. 12/945,866, filed Nov. 14, 2010, both of which areincorporated herein in their entirety by reference.

FIELD OF THE INVENTION

This disclosure relates to polycarbonate compositions and in particularto endcapped polycarbonate compositions, methods of manufacture, anduses thereof.

BACKGROUND OF THE INVENTION

Polycarbonate is a high-performance plastic with good impact strength(ductility). However, polycarbonate often has relatively limited flowproperties, which is needed in the manufacture of thin walled articles.Medium to high flow polycarbonate grades suffer from the fact that thelow temperature ductility is sacrificed for a better flow. Furthermore,polycarbonate compositions often require the use of flame-retardants tofind successful use in the manufacture of a variety of articles andcomponents.

There accordingly remains a need in the art for high flow polycarbonatecompositions and articles made from them that are transparent and flameretardant to levels acceptable by industry and in particular forthin-walled 25,000 poise applications, e.g. molded articles with 1.5 mmthickness.

SUMMARY OF THE INVENTION

The present invention provides for a composition comprising: apolycarbonate, wherein the polycarbonate comprises a repeatingstructural backbone of the following formula

wherein at least 60 percent of the total number of R¹ groups containaromatic groups and the balance thereof are aliphatic or alicyclicgroups; wherein the polycarbonate was formed in the presence of anend-capping agent and the end-capping agent is not cyanophenol; whereinthe polycarbonate has a branching level of at least about 2%; andwherein the polycarbonate has a peak melt viscosity of at least 25,000poise when measured using a parallel plate melt rheology test at aheating rate of 10° C./min at a temperature of between about 350° C. toabout 450° C. at a frequency of 3 rad/s and strain amplitude of 9%; andwherein a molded article of the polycarbonate has a UL94 V0 rating at athickness of 1.0 mm; a flame retardant; and a thermoplastic polymer thatis different than the polycarbonate; and wherein a molded article of thecomposition has a UL94 V0 rating at a thickness of 1.5 mm.

In an embodiment, a method of making a composition, comprises: preparinga polycarbonate by selecting a branching level, a desired weight averagemolecular weight, and an end-capping agent such that the polycarbonatehas a calculated peak melt viscosity of at least 25,000 poise ascalculated by a peak melt viscosity equation as follows:calculated peak meltviscosity=−57135.91+36961.39*BL+14001.13*MW^(1/3)−46944.24*pKa−322.51*BL*MW^(1/3)−2669.19*BL*pKa+215.83*MW^(1/3)*pKa+1125.63*BL²−200.11*MW^(2/3)+2231.15*pKa²,wherein BL is determined by dividing a number of moles of branchingagent by a total moles of bisphenol from which the polycarbonate isderived, the MW is the weight-averaged molecular weight of thepolycarbonate as determined by gel permeation chromatography usingpolycarbonate standards, and the pKa is the pKa of the end cappingagent; and reacting bisphenol, end-capping agent, branching agent, and acarbonate precursor wherein the polycarbonate has a repeating structuralbackbone of the following formula

wherein at least 60 percent of the total number of R¹ groups containaromatic groups and the balance thereof are aliphatic or alicyclicgroups; wherein the end-capping agent is not cyanophenol; wherein thepKa of the end-capping agent is from about 8.3 to about 11; and whereina molded article of the polycarbonate has a UL94 V0 rating at athickness of 1.0 mm; and blending with the polycarbonate a flameretardant and a thermoplastic polymer different than the polycarbonate;wherein a molded article of the composition has a UL94 V0 rating at athickness of 1.5 mm.

In an embodiment, a method of making an article of manufacture,comprises: preparing a polycarbonate by selecting a branching level, BL,a desired weight average molecular weight, and an end-capping agent suchthat the polycarbonate has a calculated peak melt viscosity of at least25,000 poise is calculated by a peak melt viscosity equation as follows:calculated peak meltviscosity=−57135.91+36961.39*BL+14001.13*MW^(1/3)−46944.24*pKa−322.51*BL*MW^(1/3)−2669.19*BL*pKa+215.83*MW^(1/3)*pKa+1125.63*BL²−200.11*MW^(2/3)+2231.15*pKa²,wherein BL is determined by dividing a number of moles of branchingagent by a total moles of bisphenol from which the polycarbonate isderived, the MW is the weight-averaged molecular weight of thepolycarbonate as determined by gel permeation chromatography usingpolycarbonate standards, and the pKa is the pKa of the end cappingagent; reacting the bisphenol, the end-capping agent, the branchingagent, and a carbonate precursor, wherein the polycarbonate comprises arepeating structural backbone of the following formula

wherein at least 60 percent of the total number of R¹ groups containaromatic groups and the balance thereof are aliphatic or alicyclicgroups; wherein the end-capping agent that is not cyanophenol; whereinan article made from the polycarbonate has a UL94 V0 rating at athickness of 1.0 mm; blending with the polycarbonate a flame retardantand a thermoplastic polymer different than the polycarbonate to form thecomposition; and forming the composition into the article; wherein anarticle made from the composition has a UL94 V0 rating at a thickness of1.5 mm.

In a further embodiment, the peak melt viscosity is at least 25,000poise calculated from the above equation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graphical representation of temperature sweep data for fourdifferent polycarbonates containing different end-capping agents,branching levels and MW (weight average molecular weight) values. Theplots were obtained using a dynamic rheometric test with parallel platesfixture. Peak Melt Viscosity values were obtained using these andsimilar plots.

DETAILED DESCRIPTION OF THE INVENTION

The word “about” should be given its ordinary and accustomed meaning andshould be relative to the word or phrase(s) that it modifies. In thecontext of pKa, the word “about” as it pertains to pKa can equal thevalue of the numeric or can equal in the range of +/−0.1 of the pKaunit, e.g. pKa of about 8.3 can include 8.2, and the word “about” as itpertains to branching level can equal the value of the numeric or canequal in the range +/−0.05% of the branching level, e.g. about 1% canencompass 0.95%. The delineation of the word about in the context pKaand branching level should not in any way limit the ordinary andaccustomed meaning of the word “about” for other language/numerics thatthe word “about” modifies.

Polycarbonate standard means polycarbonate resins whose molecularweights are considered reliable and verified by a variety of analyticalmethods. These are used to calibrate the gel permeation chromatographmolecular weight determination method.

As stated above, the present invention provides for a compositioncomprising: a flame retardant; a polycarbonate, wherein thepolycarbonate has a repeating structural background of the followingformula

wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups; wherein the polycarbonate comprises anend-capping agent and the end capping agent is not cyanophenol; whereinthe polycarbonate comprises said branching agent and said end-cappingagent and said composition has a peak melt viscosity of at least 8,000poise when measured using a parallel plate melt rheology test at aheating rate of 10° C./min at a temperature of between about 350° C. toabout 450° C.; and wherein a molded article of the composition has a UL94 V0 rating at a thickness of 1 mm, 1.5 mm, 2.0 mm, or between 1.0 mmand 2.0 mm.A. Polycarbonate Material/Structural Backbone of Said Composition

Various types of polycarbonates that have a repeating structuralbackground of the following formula:

can be utilized for the claimed invention/inventions encompassed by thisdisclosure.

The selection of a polycarbonate backbone of choice depends on manyfactors such as end use and other factors understood by one of ordinaryskill the art.

In one embodiment, the polycarbonates have repeating structuralcarbonate units of the formula (1):

wherein at least 60 percent of the total number of R¹ groups containsaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups.

In another embodiment, the polycarbonate is derived from bisphenol-A.

In another embodiment, each R¹ group is a divalent aromatic group, forexample derived from an aromatic dihydroxy compound of the formula (3):HO-A¹-Y¹-A²-OH  (3)wherein each of A¹ and A² is a monocyclic divalent arylene group, and Y¹is a single bond or a bridging group having one or two atoms thatseparate A¹ from A². In an exemplary embodiment, one atom separates A¹from A². In another embodiment, when each of A¹ and A² is phenylene, Y¹is para to each of the hydroxyl groups on the phenylenes. Illustrativenon-limiting examples of groups of this type are —O—, —S—, —S(O)—,—S(O)₂—, —C(O)—, methylene, cyclohexyl-methylene,2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene,neopentylidene, cyclohexylidene, cyclopentadecylidene,cyclododecylidene, and adamantylidene. The bridging group Y¹ can be ahydrocarbon group or a saturated hydrocarbon group such as methylene,cyclohexylidene, or isopropylidene.

Included within the scope of formula (3) are bisphenol compounds ofgeneral formula (4):

wherein R^(a) and R^(b) each represent a halogen atom or a monovalenthydrocarbon group and can be the same or different; p and q are eachindependently integers of 0 to 4; and X^(a) represents a single bond orone of the groups of formulas (5) or (6):

wherein R^(c) and R^(d) are each independently hydrogen, C₁₋₁₂ alkyl,C₁₋₁₂ cycloalkyl, C₇₋₁₂ arylalkyl, C₁₋₁₂ heteroalkyl, or cyclic C₇₋₁₂heteroarylalkyl, and R^(e) is a divalent C₁₋₁₂ hydrocarbon group. Inparticular, R^(c) and R^(d) are each the same hydrogen or C₁₋₄ alkylgroup, specifically the same C₁₋₃ alkyl group, even more specifically,methyl.

In an embodiment, R^(c) and R^(d) taken together represent a C₃₋₂₀cyclic alkylene group or a heteroatom-containing C₃₋₂₀ cyclic alkylenegroup comprising carbon atoms and heteroatoms with a valency of two orgreater. These groups can be in the form of a single saturated orunsaturated ring, or a fused polycyclic ring system wherein the fusedrings are saturated, unsaturated, or aromatic. A specificheteroatom-containing cyclic alkylene group comprises at least oneheteroatom with a valency of 2 or greater, and at least two carbonatoms. Exemplary heteroatoms in the heteroatom-containing cyclicalkylene group include —O—, —S—, and —N(Z)—, where Z is a substituentgroup selected from hydrogen, hydroxy, C₁₋₁₂ alkyl, C₁₋₁₂ alkoxy, orC₁₋₁₂ acyl.

In a specific exemplary embodiment, X^(a) is a substituted C₃₋₁₈cycloalkylidene of the formula (7):

wherein each R^(r), R^(p), R^(q), and R^(t) is independently hydrogen,halogen, oxygen, or C₁₋₁₂ organic group; I is a direct bond, a carbon,or a divalent oxygen, sulfur, or —N(Z)— wherein Z is hydrogen, halogen,hydroxy, C₁₋₁₂ alkyl, C₁₋₁₂ alkoxy, or C₁₋₁₂ acyl; h is 0 to 2, j is 1or 2, i is an integer of 0 or 1, and k is an integer of 0 to 3, with theproviso that at least two of R^(r), R^(p), R^(q), and R^(t) takentogether are a fused cycloaliphatic, aromatic, or heteroaromatic ring.It will be understood that where the fused ring is aromatic, the ring asshown in formula (7) will have an unsaturated carbon-carbon linkagewhere the ring is fused. When k is 1 and i is 0, the ring as shown informula (7) contains 4 carbon atoms, when k is 2, the ring as showncontains 5 carbon atoms, and when k is 3, the ring contains 6 carbonatoms. In one embodiment, two adjacent groups (e.g., R^(q) and R^(t)taken together) form an aromatic group, and in another embodiment, R^(q)and R^(t) taken together form one aromatic group and R^(r) and R^(p)taken together form a second aromatic group.

When k is 3 and i is 0, bisphenols containing substituted orunsubstituted cyclohexane units are used, for example bisphenols offormula (8):

wherein each R^(f) is independently hydrogen, C₁₋₁₂ alkyl, or halogen;and each R^(g) is independently hydrogen or C₁₋₁₂ alkyl. Thesubstituents can be aliphatic or aromatic, straight chain, cyclic,bicyclic, branched, saturated, or unsaturated. Suchcyclohexane-containing bisphenols, for example the reaction product oftwo moles of a phenol with one mole of a hydrogenated isophorone, areuseful for making polycarbonate polymers with high glass transitiontemperatures and high heat distortion temperatures. Cyclohexyl bisphenolcontaining polycarbonates, or a combination comprising at least one ofthe foregoing with other bisphenol polycarbonates, are supplied by BayerCo. under the APEC® trade name.

Other useful dihydroxy compounds having the formula HO—R¹—OH includearomatic dihydroxy compounds of formula (9):

wherein each R^(h) is independently a halogen atom, a C₁₋₁₀ hydrocarbylsuch as a C₁₋₁₀ alkyl group, a halogen substituted C₁₋₁₀ hydrocarbylsuch as a halogen-substituted C₁₋₁₀ alkyl group, and n is 0 to 4. Thehalogen is usually bromine.

Some illustrative examples of dihydroxy compounds include the following:4,4′-dihydroxybiphenyl, 1,6-dihydroxynaphthalene,2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane,bis(4-hydroxyphenyl)diphenylmethane,bis(4-hydroxyphenyl)-1-naphthylmethane, 1,2-bis(4-hydroxyphenyl)ethane,1,1-bis(4-hydroxyphenyl)-1-phenylethane,2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane,bis(4-hydroxyphenyl)phenylmethane,2,2-bis(4-hydroxy-3-bromophenyl)propane, 1,1-bis(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane,1,1-bis(4-hydroxyphenyl)isobutene,1,1-bis(4-hydroxyphenyl)cyclododecane,trans-2,3-bis(4-hydroxyphenyl)-2-butene,2,2-bis(4-hydroxyphenyl)adamantine, alpha,alpha′-bis(4-hydroxyphenyl)toluene, bis(4-hydroxyphenyl)acetonitrile,2,2-bis(3-methyl-4-hydroxyphenyl)propane,2,2-bis(3-ethyl-4-hydroxyphenyl)propane,2,2-bis(3-n-propyl-4-hydroxyphenyl)propane,2,2-bis(3-isopropyl-4-hydroxyphenyl)propane,2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane,2,2-bis(3-t-butyl-4-hydroxyphenyl)propane,2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,2,2-bis(3-allyl-4-hydroxyphenyl)propane,2,2-bis(3-methoxy-4-hydroxyphenyl)propane,2,2-bis(4-hydroxyphenyl)hexafluoropropane,1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene,1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene,1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene,4,4′-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone,1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycolbis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether,bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide,bis(4-hydroxyphenyl)sulfone, 9,9 to bis(4-hydroxyphenyl)fluorine,2,7-dihydroxypyrene,6,6′-dihydroxy-3,3,3′,3′-tetramethylspiro(bis)indane (“spirobiindanebisphenol”), 3,3-bis(4-hydroxyphenyl)phthalide,2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene,2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine,3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and2,7-dihydroxycarbazole, resorcinol, substituted resorcinol compoundssuch as 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol,5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl resorcinol, 5-cumylresorcinol, 2,4,5,6-tetrafluoro resorcinol, 2,4,5,6-tetrabromoresorcinol, or the like; catechol; hydroquinone; substitutedhydroquinones such as 2-methyl hydroquinone, 2-ethyl hydroquinone,2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butyl hydroquinone,2-phenyl hydroquinone, 2-cumyl hydroquinone, 2,3,5,6-tetramethylhydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone, 2,3,5,6-tetrafluorohydroquinone, 2,3,5,6-tetrabromo hydroquinone, and the like, as well ascombinations comprising at least one of the foregoing dihydroxycompounds.

Specific examples of bisphenol compounds that can be represented byformula (3) include 1,1-bis(4-hydroxyphenyl) methane,1,1-bis(4-hydroxyphenyl) ethane, 2,2-bis(4-hydroxyphenyl) propane(hereinafter “bisphenol A” or “BPA”), 2,2-bis(4-hydroxyphenyl) butane,2,2-bis(4-hydroxyphenyl) octane, 1,1-bis(4-hydroxyphenyl) propane,1,1-bis(4-hydroxyphenyl) n-butane, 2,2-bis(4-hydroxy-1-methylphenyl)propane, 1,1-bis(4-hydroxy-t-butylphenyl) propane,3,3-bis(4-hydroxyphenyl) phthalimidine,2-phenyl-3,3-bis(4-hydroxyphenyl) phthalimidine (PPPBP), and1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC). Combinationscomprising at least one of the foregoing dihydroxy compounds can also beused.

“Polycarbonate” as used herein includes homopolycarbonates, copolymerscomprising different R¹ moieties in the carbonate (referred to herein as“copolycarbonates”), and copolymers comprising carbonate units and othertypes of polymer units, such as ester units. In one specific embodiment,the polycarbonate is a linear homopolymer or copolymer comprising unitsderived from bisphenol A, in which each of A¹ and A² is p-phenylene andY¹ is isopropylidene in formula (3). More specifically, at least 60%,particularly at least 80% of the R¹ groups in the polycarbonate arederived from bisphenol A.

Another specific type of copolymer is a polyester carbonate, also knownas a polyester-polycarbonate. Such copolymers further contain, inaddition to recurring carbonate chain units of the formula (1),repeating units of formula (10):

wherein D is a divalent group derived from a dihydroxy compound, and canbe, for example, a C₂₋₁₀ alkylene group, a C₆₋₂₀ alicyclic group, aC₆₋₂₀ aromatic group or a polyoxyalkylene group in which the alkylenegroups contain 2 to 6 carbon atoms, specifically 2, 3, or 4 carbonatoms; and T divalent group derived from a dicarboxylic acid, and canbe, for example, a C₂₋₁₀ alkylene group, a C₆₋₂₀ alicyclic group, aC₆₋₂₀ alkyl aromatic group, or a C₆₋₂₀ aromatic group.

In one embodiment, D is a C₂₋₃₀ alkylene group having a straight chain,branched chain, or cyclic (including polycyclic) structure. In anotherembodiment, D is derived from an aromatic dihydroxy compound of formula(4) above. In another embodiment, D is derived from an aromaticdihydroxy compound of formula (9) above.

Examples of aromatic dicarboxylic acids that can be used to prepare thepolyester units include isophthalic or terephthalic acid,1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether,4,4′-bisbenzoic acid, and combinations comprising at least one of theforegoing acids. Acids containing fused rings can also be present, suchas in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids. Specificdicarboxylic acids are terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexane dicarboxylic acid, or combinationsthereof. A specific dicarboxylic acid comprises a combination ofisophthalic acid and terephthalic acid wherein the weight ratio ofisophthalic acid to terephthalic acid is 91:9 to 2:98. In anotherspecific embodiment, D is a C₂₋₆ alkylene group and T is p-phenylene,m-phenylene, naphthalene, a divalent cycloaliphatic group, or acombination thereof. This class of polyester includes the poly(alkyleneterephthalates).

The molar ratio of ester units to carbonate units in the copolymers canvary broadly, for example 1:99 to 99:1, specifically 10:90 to 90:10,more specifically 25:75 to 75:25, depending on the desired properties ofthe final composition.

In a specific embodiment, the polyester unit of apolyester-polycarbonate can be derived from the reaction of acombination of isophthalic and terephthalic diacids (or derivativesthereof) with resorcinol. In another specific embodiment, the polyesterunit of a polyester-polycarbonate is derived from the reaction of acombination of isophthalic acid and terephthalic acid with bisphenol-A.In a specific embodiment, the polycarbonate units are derived frombisphenol A. In another specific embodiment, the polycarbonate units arederived from resorcinol and bisphenol A in a molar ratio of resorcinolcarbonate units to bisphenol A carbonate units of 1:99 to 99:1.

A specific example of a polycarbonate-polyester is acopolycarbonate-polyester-polysiloxane terpolymer comprising carbonateunits of formula (1), ester units of formula (10), and polysiloxane(also referred to herein as “polydiorganosiloxane”) units of formula(11):

wherein each occurrence of R is same or different, and is a C₁₋₁₃monovalent organic group. For example, R may independently be a C₁₋₁₃alkyl group, C₁₋₁₃ alkoxy group, C₂₋₁₃ alkenyl group, C₂₋₁₃ alkenyloxygroup, C₃₋₆ cycloalkyl group, C₃₋₆ cycloalkoxy group, C₆₋₁₄ aryl group,C₆₋₁₀ aryloxy group, C₇₋₁₃ arylalkyl group, C₇₋₁₃ arylalkoxy group,C₇₋₁₃ alkylaryl group, or C₇₋₁₃ alkylaryloxy group. The foregoing groupsmay be fully or partially halogenated with fluorine, chlorine, bromine,or iodine, or a combination thereof. Combinations of the foregoing Rgroups may be used in the same copolymer. In an embodiment, thepolysiloxane comprises R groups that have a minimum hydrocarbon content.In a specific embodiment, an R group with a minimum hydrocarbon contentis a methyl group.

The value of E in formula (11) may vary widely depending on the type andrelative amount of each component in the thermoplastic composition, thedesired properties of the composition, and like considerations. Herein,E has an average value of 4 to 50. In an embodiment, E has an averagevalue of 16 to 50, specifically 20 to 45, and more specifically 25 to45. In another embodiment, E has an average value of 4 to 15,specifically 5 to 15, more specifically 6 to 15, and still morespecifically 7 to 12.

In an embodiment, polydiorganosiloxane units are derived from dihydroxyaromatic compound of formula (12):

wherein E is as defined above; each R may independently be the same ordifferent, and is as defined above; and each Ar may independently be thesame or different, and is a substituted or unsubstituted C₆₋₃₀ arylenegroup, wherein the bonds are directly connected to an aromatic moiety.Suitable Ar groups in formula (12) may be derived from a C₆₋₃₀ dihydroxyaromatic compound, for example a dihydroxy aromatic compound of formula(3), (4), (8), or (9) above. Combinations comprising at least one of theforegoing dihydroxy aromatic compounds may also be used. Exemplarydihydroxy aromatic compounds are resorcinol (i.e.,1,3-dihydroxybenzene), 4-methyl-1,3-dihydroxybenzene,5-methyl-1,3-dihydroxybenzene, 4,6-dimethyl-1,3-dihydroxybenzene,1,4-dihydroxybenzene, 1,1-bis(4-hydroxyphenyl) methane,1,1-bis(4-hydroxyphenyl) ethane, 2,2-bis(4-hydroxyphenyl) propane,2,2-bis(4-hydroxyphenyl) butane, 2,2-bis(4-hydroxyphenyl) octane,1,1-bis(4-hydroxyphenyl) propane, 1,1-bis(4-hydroxyphenyl) n-butane,2,2-bis(4-hydroxy-1-methylphenyl) propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl sulfide), and1,1-bis(4-hydroxy-t-butylphenyl) propane. Combinations comprising atleast one of the foregoing dihydroxy compounds may also be used. In anembodiment, the dihydroxy aromatic compound is unsubstituted, or is notsubstituted with non-aromatic hydrocarbon-containing substituents suchas, for example, alkyl, alkoxy, or alkylene substituents.

In a specific embodiment, where Ar is derived from resorcinol, thepolydiorganosiloxane repeating units are derived from dihydroxy aromaticcompounds of formula (13):

or, where Ar is derived from bisphenol-A, from dihydroxy aromaticcompounds of formula (14):

wherein E is as defined above.

In another embodiment, polydiorganosiloxane units are derived fromdihydroxy aromatic compound of formula (15):

wherein R and E are as described above, and each occurrence of R² isindependently a divalent C₁₋₃₀ alkylene or C₇₋₃₀ arylene-alkylene, andwherein the polymerized polysiloxane unit is the reaction residue of itscorresponding dihydroxy aromatic compound. In a specific embodiment,where R² is C₇₋₃₀ arylene-alkylene, the polydiorganosiloxane units arederived from dihydroxy aromatic compound of formula (16):

wherein R and E are as defined above. Each R³ is independently adivalent C₂₋₈ aliphatic group. Each M may be the same or different, andmay be a halogen, cyano, nitro, C₁₋₈ alkylthio, C₁₋₈ alkyl, C₁₋₈ alkoxy,C₂₋₈ alkenyl, C₂₋₈ alkenyloxy group, C₃₋₈ cycloalkyl, C₃₋₈ cycloalkoxy,C₆₋₁₀ aryl, C₆₋₁₀ aryloxy, C₇₋₁₂ arylalkyl, C₇₋₁₂ arylalkoxy, C₇₋₁₂alkylaryl, or C₇₋₁₂ alkylaryloxy, wherein each n is independently 0, 1,2, 3, or 4.

In an embodiment, M is bromo or chloro, an alkyl group such as methyl,ethyl, or propyl, an alkoxy group such as methoxy, ethoxy, or propoxy,or an aryl group such as phenyl, chlorophenyl, or tolyl; R³ is adimethylene, trimethylene or tetramethylene group; and R is a C₁₋₈alkyl, haloalkyl such as trifluoropropyl, cyanoalkyl, or aryl such asphenyl, chlorophenyl or tolyl. In another embodiment, R is methyl, or acombination of methyl and trifluoropropyl, or a combination of methyland phenyl. In still another embodiment, M is methoxy, n is 0 or 1, R³is a divalent C₁₋₃ aliphatic group, and R is methyl.

In a specific embodiment, the polydiorganosiloxane units are derivedfrom a dihydroxy aromatic compound of formula (17):

wherein E is as described above.

In another specific embodiment, the polydiorganosiloxane units arederived from dihydroxy aromatic compound of formula (18):

wherein E is as defined above.

Dihydroxy polysiloxanes typically can be made by functionalizing asubstituted siloxane oligomer of formula (19):

wherein R and E are as previously defined, and Z is H, halogen (Cl, Br,I), or carboxylate. Exemplary carboxylates include acetate, formate,benzoate, and the like. In an exemplary embodiment, where Z is H,compounds of formula (19) may be prepared by platinum catalyzed additionwith an aliphatically unsaturated monohydric phenol. Suitablealiphatically unsaturated monohydric phenols included, for example,eugenol, 2-allylphenol, 4-allylphenol, 4-allyl-2-methylphenol,4-allyl-2-phenylphenol, 4-allyl-2-bromophenol, 4-allyl-2-t-butoxyphenol,4-phenyl-2-allylphenol, 2-methyl-4-propenylphenol,2-allyl-4,6-dimethylphenol, 2-allyl-4-bromo-6-methylphenol,2-allyl-6-methoxy-4-methylphenol, and 2-allyl-4,6-dimethylphenol.Combinations comprising at least one of the foregoing may also be used.Where Z is halogen or carboxylate, functionalization may be accomplishedby reaction with a dihydroxy aromatic compound of formulas (3), (4),(8), (9), or a combination comprising at least one of the foregoingdihydroxy aromatic compounds. In an exemplary embodiment, compounds offormula (12) may be formed from an alpha,omega-bisacetoxypolydiorangonosiloxane and a dihydroxy aromatic compoundunder phase transfer conditions.

Specific copolycarbonate terpolymers include those with polycarbonateunits of formula (1) wherein R¹ is a C₆₋₃₀ arylene group, polysiloxaneunits derived from siloxane diols of formula (14), (17) or (18), andpolyester units wherein T is a C₆₋₃₀ arylene group. In an embodiment, Tis derived from isophthalic and/or terephthalic acid, or reactivechemical equivalents thereof. In another embodiment, R¹ is derived fromthe carbonate reaction product of a resorcinol of formula (9), or acombination of a resorcinol of formula (9) and a bisphenol of formula(4).

The relative amount of each type of unit in the foregoing terpolymerwill depend on the desired properties of the terpolymer, and are readilydetermined by one of ordinary skill in the art with out undueexperimentation, using the guidelines provided herein. For example, thepolycarbonate-polyester-polysiloxane terpolymer can comprise siloxaneunits in an amount of 0.1 to 25 weight percent (wt. %), specifically 0.2to 10 wt. %, more specifically 0.2 to 6 wt. %, even more specifically0.2 to 5 wt. %, and still more specifically 0.25 to 2 wt. %, based onthe total weight of the polycarbonate-polyester-polysiloxane terpolymer,with the proviso that the siloxane units are provided by polysiloxaneunits covalently bonded in the polymer backbone of thepolycarbonate-polyester-polysiloxane terpolymer. Thepolycarbonate-polyester-polysiloxane terpolymer can further comprise 0.1to 49.85 wt. % carbonate units, 50 to 99.7 wt. % ester units, and 0.2 to6 wt. % polysiloxane units, based on the total weight of thepolysiloxane units, ester units, and carbonate units. Alternatively, thepolycarbonate-polyester-polysiloxane terpolymer comprises 0.25 to 2 wt.% polysiloxane units, 60 to 96.75 wt. % ester units, and 3.25 to 39.75wt. % carbonate units, based on the total weight of the polysiloxaneunits, ester units, and carbonate units.

Various types of thermoplastic compositions are encompassed by theclaimed invention/inventions encompassed by this disclosure.

In one embodiment, the polycarbonate is selected from at least one ofthe following: a homopolycarbonate derived from a bisphenol; acopolycarbonate derived from more than one bisphenol; and a copolymerderived from one or more bisphenols and having one or more aliphaticester units or aromatic ester units or siloxane units.

In another embodiment, in addition to the endcapped polycarbonatesdescribed above, the thermoplastic compositions can also comprise otherthermoplastic polymers, for example polyesters, polyamides, and otherpolycarbonate homopolymers and copolymers, includingpolycarbonate-polysiloxane copolymers and polyester carbonates, alsoknown as a polyester-polycarbonates, and polyesters. The polymercomponent of such compositions can comprise 1 to 99 wt. %, specifically10 to 90 wt. %, more specifically 20 to 80 wt. % of the cyanophenylendcapped polycarbonate, with the remainder of the polymer componentbeing other polymers.

In another embodiment, a second polycarbonate is formulated with thecomposition, wherein a second polycarbonate comprises a repeatingstructure of

wherein said second polycarbonate is different from said polycarbonateand wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups.

In another embodiment, the second polycarbonate is derived frombisphenol-A.

B. Branching Agents

The polycarbonates of the claimed invention contain branchedpolycarbonate(s). Various types of branching agents can be utilized forthe claimed invention/inventions encompassed by this disclosure.

Branched polycarbonate blocks can be prepared by adding a branchingagent during polymerization. These branching agents includepolyfunctional organic compounds containing at least three functionalgroups selected from hydroxyl, carboxyl, carboxylic anhydride,haloformyl, and mixtures of the foregoing functional groups. Specificexamples include trimellitic acid, trimellitic anhydride, trimellitictrichloride (TMTC), tris-p-hydroxy phenyl ethane (THPE),3,3-bis-(4-hydroxyphenyl)-oxindole (also known as isatin-bis-phenol),tris-phenol TC (1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene),tris-phenol PA (4(4(1,1-bis(p-hydroxyphenyl)-ethyl) alpha,alpha-dimethyl benzyl)phenol), 4-chloroformyl phthalic anhydride,trimesic acid, and benzophenone tetracarboxylic acid. The branchingagents can be added at a level of 0.05 to 2.0 wt. %. Mixtures comprisinglinear polycarbonates and branched polycarbonates can be used.

In some embodiments, a particular type of branching agent is used tocreate branched polycarbonate materials. These branched polycarbonatematerials have statistically more than two end groups. The branchingagent is added in an amount (relative to the bisphenol monomer) that issufficient to achieve the desired branching content, that is, more thantwo end groups. The molecular weight of the polymer may become very highupon addition of the branching agent and may lead to viscosity problemsduring phosgenation. Therefore, in some embodiments, an increase in theamount of the chain termination agent is used in the polymerization. Theamount of chain termination agent used when the particular branchingagent is used is generally higher than if only a chain termination agentalone is used. The amount of chain termination agent used is generallyabove 5 mole percent and less than 20 mole percent compared to thebisphenol monomer.

In some embodiments, the branching agent is a structure derived from atriacid trichloride of the formula (21)

wherein Z is hydrogen, a halogen, C₁₋₃ alkyl group, C₁₋₃ alkoxy group,C₇₋₁₂ arylalkyl, alkylaryl, or nitro group, and z is 0 to 3; or abranching agent derived from a reaction with a tri-substituted phenol ofthe formula (22)

wherein T is a C₁₋₂₀ alkyl group, C₁₋₂₀ alkyleneoxy group, C₇₋₁₂arylalkyl, or alkylaryl group, S is hydrogen, a halogen, C₁₋₃ alkylgroup, C₁₋₃ alkoxy group, C₇₋₁₂ arylalkyl, alkylaryl, or nitro group, sis 0 to 4.

In another embodiment, the branching agent is a structure having formula(23)

Examples of specific branching agents that are particularly effective inthe compositions include trimellitic trichloride (TMTC), tris-p-hydroxyphenyl ethane (THPE) and isatin-bis-phenol. In one embodiment, informula (21), z is hydrogen and z is 3. In another embodiment, informula (22), S is hydrogen, T is methyl and s is 4.

The relative amount of branching agents used in the manufacture of thepolymer will depend on a number of considerations, for example the typeof R¹ groups, the amount of cyanophenol, and the desired molecularweight of the polycarbonate. In general, the amount of branching agentis effective to provide about 0.1 to 10 branching units per 100 R¹units, specifically about 0.5 to 8 branching units per 100 R¹ units, andmore specifically about 0.75 to 5 branching units per 100 R¹ units. Forbranching agents having formula (21), the amount of branching agenttri-ester groups are present in an amount of about 0.1 to 10 branchingunits per 100 R¹ units, specifically about 0.5 to 8 branching units per100 R¹ units, and more specifically about 0.75 to 5 tri-ester units per100 R¹ units. For branching agents having formula (22), the amount ofbranching agent tricarbonate groups are present in an amount of about0.1 to 10 branching units per 100 R¹ units, specifically about 0.5 to 8branching units per 100 R¹ units, and more specifically about 0.75 to 5tri-phenylcarbonate units per 100 R¹ units. In some embodiments, acombination of two or more branching agents may be used.

In one embodiment, the polycarbonate of said composition has a branchinglevel of at least about 1% or at least about 2% or at least about 3% orfrom about 1% to about 3%.

C. End-Capping Agents

Various types of end-capping agents can be utilized for the claimedinvention/inventions encompassed by this disclosure.

In one embodiment, the end-capping agent is selected based upon themolecular weight of said polycarbonate and said branching level impartedby said branching agent. The desired goal is achieve a thin walledarticle with good flame retardance, e.g. a composition wherein a moldedarticle of the composition has a UL 94 V0 rating at a thickness of 1 mm,1.5 mm, 2.0 mm, or between 1.0 mm and 2.0 mm.

Without being bound by theory, the pKa of the end-capping agent is ofimportance in achieving a thin-walled article of manufacture with a V0rating. The pKa of an end-capping agent is a measure of its relativeacidity. The lower the pKa value of the end-capping agent the moreacidic the end-capping agent. It was unexpectedly observed that the pKaof an end-capping agent is one indicator of the flame retardancy of thebranched polycarbonate. For example lower pKas provide better flameretardant properties than higher pKas for branched polycarbonates.

In one embodiment, the end-capping agent has a pKa between about 8.3 andabout 11. In a further embodiment, the end-capping agent has a pKa ofbetween 9 and 11.

In another embodiment, the end-capping agents are selected from at leastone of the following: phenol or a phenol containing one or moresubstitutions with at least one of the following: aliphatic groups,olefinic groups, aromatic groups, halogens, ester groups, and ethergroups.

Of particular usefulness commercially, in another embodiment, theend-capping agents are selected from at least one of the following:phenol, para-t-butylphenol or para-cumylphenol.

D. Additives for End-Capped Polycarbonate Compositions

Various types of flame retardants can be utilized in the claimedinvention/inventions encompassed by this disclosure.

In one embodiment, the flame retardant additives include, for example,flame retardant salts such as alkali metal salts of perfluorinated C₁₋₁₆alkyl sulfonates such as potassium perfluorobutane sulfonate (Rimarsalt), potassium perfluoroctane sulfonate, tetraethylammoniumperfluorohexane sulfonate, potassium diphenylsulfone sulfonate (KSS),and the like; and salts formed by reacting for example an alkali metalor alkaline earth metal (for example lithium, sodium, potassium,magnesium, calcium and barium salts) and an inorganic acid complex salt,for example, an oxo-anion, such as alkali metal and alkaline-earth metalsalts of carbonic acid, such as Na₂CO₃, K₂CO₃, MgCO₃, CaCO₃, and BaCO₃or fluoro-anion complex such as Li₃AlF₆, BaSiF₆, KBF₄, K₃AlF₆, KAlF₄,K₂SiF₆, and/or Na₃AlF₆ or the like. Rimar salt and KSS, alone or incombination with other flame retardants, are particularly useful in thepolycarbonate compositions disclosed herein.

In another embodiment, the flame-retardants are selected from at leastone of the following: alkali metal salts of perfluorinated C₁₋₁₆ alkylsulfonates; potassium perfluorobutane sulfonate; potassiumperfluoroctane sulfonate; tetraethylammonium perfluorohexane sulfonate;and potassium diphenylsulfone sulfonate.

In another embodiment, the flame retardant is not a bromine or chlorinecontaining composition.

In another embodiment, the flame retardant additives include organiccompounds that include phosphorus, bromine, and/or chlorine.Non-brominated and non-chlorinated phosphorus-containing flameretardants can be used in certain applications for regulatory reasons,for example organic phosphates and organic compounds containingphosphorus-nitrogen bonds. One type of exemplary organic phosphate is anaromatic phosphate of the formula (GO)₃P═O, wherein each G isindependently an alkyl, cycloalkyl, aryl, alkylaryl, or arylalkyl group,provided that at least one G is an aromatic group. Two of the G groupscan be joined together to provide a cyclic group, for example, diphenylpentaerythritol diphosphate. Exemplary aromatic phosphates include,phenyl bis(dodecyl) phosphate, phenyl bis(neopentyl) phosphate, phenylbis(3,5,5′-trimethylhexyl) phosphate, ethyl diphenyl phosphate,2-ethylhexyl di(p-tolyl) phosphate, bis(2-ethylhexyl) p-tolyl phosphate,tritolyl phosphate, bis(2-ethylhexyl) phenyl phosphate, tri(nonylphenyl)phosphate, bis(dodecyl) p-tolyl phosphate, dibutyl phenyl phosphate,2-chloroethyl diphenyl phosphate, p-tolyl bis(2,5,5′-trimethylhexyl)phosphate, 2-ethylhexyl diphenyl phosphate, or the like. A specificaromatic phosphate is one in which each G is aromatic, for example,triphenyl phosphate, tricresyl phosphate, isopropylated triphenylphosphate, and the like.

Di- or poly-functional aromatic phosphorus-containing compounds are alsouseful, for example, compounds of the formulas below:

wherein each G¹ is independently a hydrocarbon having 1 to 30 carbonatoms; each G² is independently a hydrocarbon or hydrocarbonoxy having 1to 30 carbon atoms; each X is independently a bromine or chlorine; m is0 to 4, and n is 1 to 30. Exemplary di- or polyfunctional aromaticphosphorus-containing compounds include resorcinol tetraphenyldiphosphate (RDP), the bis(diphenyl) phosphate of hydroquinone and thebis(diphenyl) phosphate of bisphenol-A, respectively, their oligomericand polymeric counterparts, and the like.

Exemplary flame retardant additives containing phosphorus-nitrogen bondsinclude phosphonitrilic chloride, phosphorus ester amides, phosphoricacid amides, phosphonic acid amides, phosphinic acid amides,tris(aziridinyl) phosphine oxide.

Halogenated organic flame retardant compounds can also be used as flameretardants, for example halogenated flame retardant compounds of formula(20):

wherein R is a C₁₋₃₆ alkylene, alkylidene or cycloaliphatic linkage,e.g., methylene, ethylene, propylene, isopropylene, isopropylidene,butylene, isobutylene, amylene, cyclohexylene, cyclopentylidene, or thelike; or an oxygen ether, carbonyl, amine, or a sulfur-containinglinkage, e.g., sulfide, sulfoxide, sulfone, or the like. R can alsoconsist of two or more alkylene or alkylidene linkages connected by suchgroups as aromatic, amino, ether, carbonyl, sulfide, sulfoxide, sulfone,or the like.

Ar and Ar′ in formula (20) are each independently mono- orpolycarbocyclic aromatic groups such as phenylene, biphenylene,terphenylene, naphthylene, or the like.

Y is an organic, inorganic, or organometallic radical, for example (1)halogen, e.g., chlorine, bromine, iodine, fluorine or (2) ether groupsof the general formula OB, wherein B is a monovalent hydrocarbon groupsimilar to X or (3) monovalent hydrocarbon groups of the typerepresented by R or (4) other substituents, e.g., nitro, cyano, and thelike, said substituents being essentially inert provided that there isgreater than or equal to one, specifically greater than or equal to two,halogen atoms per aryl nucleus.

When present, each X is independently a monovalent hydrocarbon group,for example an alkyl group such as methyl, ethyl, propyl, isopropyl,butyl, decyl, or the like; an aryl groups such as phenyl, naphthyl,biphenyl, xylyl, tolyl, or the like; and aralkyl group such as benzyl,ethylphenyl, or the like; a cycloaliphatic group such as cyclopentyl,cyclohexyl, or the like. The monovalent hydrocarbon group can itselfcontain inert substituents.

Each d is independently 1 to a maximum equivalent to the number ofreplaceable hydrogens substituted on the aromatic rings comprising Ar orAr′. Each e is independently 0 to a maximum equivalent to the number ofreplaceable hydrogens on R. Each a, b, and c is independently a wholenumber, including 0. When b is not 0, neither a nor c can be 0.Otherwise either a or c, but not both, can be 0. Where b is 0, thearomatic groups are joined by a direct carbon-carbon bond.

The hydroxyl and Y substituents on the aromatic groups, Ar and Ar′ canbe varied in the ortho, meta or para positions on the aromatic rings andthe groups can be in any possible geometric relationship with respect toone another.

Included within the scope of the above formula are bisphenols of whichthe following are representative: 2,2-bis-(3,5-dichlorophenyl)-propane;bis-(2-chlorophenyl)-methane; bis(2,6-dibromophenyl)-methane;1,1-bis-(4-iodophenyl)-ethane; 1,2-bis-(2,6-dichlorophenyl)-ethane;1,1-bis-(2-chloro-4-iodophenyl)ethane;1,1-bis-(2-chloro-4-methylphenyl)-ethane;1,1-bis-(3,5-dichlorophenyl)-ethane;2,2-bis-(3-phenyl-4-bromophenyl)-ethane;2,6-bis-(4,6-dichloronaphthyl)-propane;2,2-bis-(2,6-dichlorophenyl)-pentane;2,2-bis-(3,5-dibromophenyl)-hexane; bis-(4-chlorophenyl)-phenyl-methane;bis-(3,5-dichlorophenyl)-cyclohexylmethane;bis-(3-nitro-4-bromophenyl)-methane;bis-(4-hydroxy-2,6-dichloro-3-methoxyphenyl)-methane; and2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane 2,2bis-(3-bromo-4-hydroxyphenyl)-propane. Also included within the abovestructural formula are: 1,3-dichlorobenzene, 1,4-dibromobenzene,1,3-dichloro-4-hydroxybenzene, and biphenyls such as2,2′-dichlorobiphenyl, polybrominated 1,4-diphenoxybenzene,2,4′-dibromobiphenyl, and 2,4′-dichlorobiphenyl as well as decabromodiphenyl oxide, and the like.

Another useful class of flame retardant is the class of cyclic siloxaneshaving the general formula (R₂SiO)_(y) wherein R is a monovalenthydrocarbon or fluorinated hydrocarbon having from 1 to 18 carbon atomsand y is a number from 3 to 12. Examples of fluorinated hydrocarboninclude, but are not limited to, 3-fluoropropyl, 3,3,3-trifluoropropyl,5,5,5,4,4,3,3-heptafluoropentyl, fluorophenyl, difluorophenyl andtrifluorotolyl. Examples of suitable cyclic siloxanes include, but arenot limited to, octamethylcyclotetrasiloxane,1,2,3,4-tetramethyl-1,2,3,4-tetravinylcyclotetrasiloxane,1,2,3,4-tetramethyl-1,2,3,4-tetraphenylcyclotetrasiloxane,octaethylcyclotetrasiloxane, octapropylcyclotetrasiloxane,octabutylcyclotetrasiloxane, decamethylcyclopentasiloxane,dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane,hexadecamethylcyclooctasiloxane, eicosamethylcyclodecasiloxane,octaphenylcyclotetrasiloxane, and the like. A particularly useful cyclicsiloxane is octaphenylcyclotetrasiloxane.

When present, the foregoing flame retardant additives are generallypresent in amounts of 0.01 to 10 wt. %, more specifically 0.02 to 5 wt.%, based on 100 parts by weight of the polymer component of thethermoplastic composition.

In another embodiment the thermoplastic composition can further includean impact modifier(s), with the proviso that the additives are selectedso as to not significantly adversely affect the desired properties ofthe thermoplastic composition. Suitable impact modifiers are typicallyhigh molecular weight elastomeric materials derived from olefins,monovinyl aromatic monomers, acrylic and methacrylic acids and theirester derivatives, as well as conjugated dienes. The polymers formedfrom conjugated dienes can be fully or partially hydrogenated. Theelastomeric materials can be in the form of homopolymers or copolymers,including random, block, radial block, graft, and core-shell copolymers.Combinations of impact modifiers can be used.

A specific type of impact modifier is an elastomer-modified graftcopolymer comprising (i) an elastomeric (i.e., rubbery) polymersubstrate having a glass transition temperature (T_(g)) less than 10°C., more specifically less than −10° C., or more specifically −40 to−80° C., and (ii) a rigid polymeric superstrate grafted to theelastomeric polymer substrate. Materials suitable for use as theelastomeric phase include, for example, conjugated diene rubbers, forexample polybutadiene and polyisoprene; copolymers of a conjugated dienewith less than 50 wt. % of a copolymerizable monomer, for example amonovinylic compound such as styrene, acrylonitrile, n-butyl acrylate,or ethyl acrylate; olefin rubbers such as ethylene propylene copolymers(EPR) or ethylene-propylene-diene monomer rubbers (EPDM); ethylene-vinylacetate rubbers; silicone rubbers; elastomeric C₁₋₈ alkyl(meth)acrylates; elastomeric copolymers of C₁₋₈ alkyl (meth)acrylateswith butadiene and/or styrene; or combinations comprising at least oneof the foregoing elastomers. Materials suitable for use as the rigidphase include, for example, monovinyl aromatic monomers such as styreneand alpha-methyl styrene, and monovinylic monomers such asacrylonitrile, acrylic acid, methacrylic acid, and the C₁₋₆ esters ofacrylic acid and methacrylic acid, specifically methyl methacrylate. Asused herein, the term “(meth)acrylate” encompasses both acrylate andmethacrylate groups.

Specific exemplary elastomer-modified graft copolymers include thoseformed from styrene-butadiene-styrene (SBS), styrene-butadiene rubber(SBR), styrene-ethylene-butadiene-styrene (SEBS), ABS(acrylonitrile-butadiene-styrene),acrylonitrile-ethylene-propylene-diene-styrene (AES),styrene-isoprene-styrene (SIS), methyl methacrylate-butadiene-styrene(MBS), and styrene-acrylonitrile (SAN).

Impact modifiers, when present, are generally present in amounts of 1 to30 wt. %, based on 100 parts by weight of the polymer component of thethermoplastic composition.

In addition to the endcapped polycarbonate and flame retardant (and anyimpact modifier, if used), the thermoplastic composition can includevarious additives ordinarily incorporated in polycarbonate compositionsof this type, with the proviso that the additives are selected so as tonot significantly adversely affect the desired properties of thepolycarbonate, for example, transparency and flame retardance.Combinations of additives can be used. Such additives can be mixed at asuitable time during the mixing of the components for forming thecomposition.

Various additives can be incorporated into the composition of mattersencompassed by this disclosure/claimed invention.

In one embodiment, one or more additives are selected from at least oneof the following: UV stabilizing additives, thermal stabilizingadditives, mold release agents, colorants, organic and inorganicfillers, and gamma-stabilizing agents.

Possible fillers or reinforcing agents include, for example, silicatesand silica powders such as aluminum silicate (mullite), syntheticcalcium silicate, zirconium silicate, fused silica, crystalline silicagraphite, natural silica sand, or the like; boron powders such asboron-nitride powder, boron-silicate powders, or the like; oxides suchas TiO₂, aluminum oxide, magnesium oxide, or the like; calcium sulfate(as its anhydride, dihydrate or trihydrate); calcium carbonates such aschalk, limestone, marble, synthetic precipitated calcium carbonates, orthe like; talc, including fibrous, modular, needle shaped, lamellartalc, or the like; wollastonite; surface-treated wollastonite; glassspheres such as hollow and solid glass spheres, silicate spheres,cenospheres, aluminosilicate (armospheres), or the like; kaolin,including hard kaolin, soft kaolin, calcined kaolin, kaolin comprisingvarious coatings known in the art to facilitate compatibility with thepolycarbonate polymeric matrix, or the like; single crystal fibers or“whiskers” such as silicon carbide, alumina, boron carbide, iron,nickel, copper, or the like; fibers (including continuous and choppedfibers) such as asbestos, carbon fibers, glass fibers, such as E, A, C,ECR, R, S, D, or NE glasses, or the like; sulfides such as molybdenumsulfide, zinc sulfide or the like; barium compounds such as bariumtitanate, barium ferrite, barium sulfate, heavy spar, or the like;metals and metal oxides such as particulate or fibrous aluminum, bronze,zinc, copper and nickel or the like; flaked fillers such as glassflakes, flaked silicon carbide, aluminum diboride, aluminum flakes,steel flakes or the like; fibrous fillers, for example short inorganicfibers such as those derived from blends comprising at least one ofaluminum silicates, aluminum oxides, magnesium oxides, and calciumsulfate hemihydrate or the like; natural fillers and reinforcements,such as wood flour obtained by pulverizing wood, fibrous products suchas cellulose, cotton, sisal, jute, starch, cork flour, lignin, groundnut shells, corn, rice grain husks or the like; organic fillers such aspolytetrafluoroethylene; reinforcing organic fibrous fillers formed fromorganic polymers capable of forming fibers such as poly(ether ketone),polyimide, polybenzoxazole, poly(phenylene sulfide), polyesters,polyethylene, aromatic polyamides, aromatic polyimides, polyetherimides,polytetrafluoroethylene, acrylic resins, poly(vinyl alcohol) or thelike; as well as additional fillers and reinforcing agents such as mica,clay, feldspar, flue dust, fillite, quartz, quartzite, perlite, tripoli,diatomaceous earth, carbon black, or the like, or combinationscomprising at least one of the foregoing fillers or reinforcing agents.

The fillers and reinforcing agents can be coated with a layer ofmetallic material to facilitate conductivity, or surface treated withsilanes to improve adhesion and dispersion with the polycarbonatepolymeric matrix. In addition, the reinforcing fillers can be providedin the form of monofilament or multifilament fibers and can be usedindividually or in combination with other types of fiber, through, forexample, co-weaving or core/sheath, side-by-side, orange-type or matrixand fibril constructions, or by other methods known to one skilled inthe art of fiber manufacture. Exemplary co-woven structures include, forexample, glass fiber-carbon fiber, carbon fiber-aromatic polyimide(aramid) fiber, and aromatic polyimide fiberglass fiber or the like.Fibrous fillers can be supplied in the form of, for example, rovings,woven fibrous reinforcements, such as 0-90 degree fabrics or the like;non-woven fibrous reinforcements such as continuous strand mat, choppedstrand mat, tissues, papers and felts or the like; or three-dimensionalreinforcements such as braids. Fillers are generally used in amounts of0 to 80 parts by weight, based on 100 parts by weight of the polymercomponent of the composition.

Exemplary antioxidant additives include, for example, organophosphitessuch as tris(nonyl phenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite(“IRGAFOS 168” or “I-168”), bis(2,4-di-t-butylphenyl)pentaerythritoldiphosphite, distearyl pentaerythritol diphosphite or the like;alkylated monophenols or polyphenols; alkylated reaction products ofpolyphenols with dienes, such astetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane,or the like; butylated reaction products of para-cresol ordicyclopentadiene; alkylated hydroquinones; hydroxylated thiodiphenylethers; alkylidene-bisphenols; benzyl compounds; esters ofbeta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid with monohydricor polyhydric alcohols; esters ofbeta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid withmonohydric or polyhydric alcohols; esters of thioalkyl or thioarylcompounds such as distearylthiopropionate, dilaurylthiopropionate,ditridecylthiodipropionate,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionateor the like; amides ofbeta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid or the like, orcombinations comprising at least one of the foregoing antioxidants.Antioxidants are generally used in amounts of 0.0001 to 1 part byweight, based on 100 parts by weigh of the polymer component of thethermoplastic composition (excluding any filler).

Exemplary heat stabilizer additives include, for example,organophosphites such as triphenyl phosphite,tris-(2,6-dimethylphenyl)phosphite, tris-(mixed mono- anddi-nonylphenyl)phosphite or the like; phosphonates such asdimethylbenzene phosphonate or the like, phosphates such as trimethylphosphate, or the like, or combinations comprising at least one of theforegoing heat stabilizers. Heat stabilizers are generally used inamounts of 0.0001 to 1 part by weight, based on 100 parts by weight ofthe polymer component of the thermoplastic composition.

Light stabilizers and/or ultraviolet light (UV) absorbing additives canalso be used. Exemplary light stabilizer additives include, for example,benzotriazoles such as 2-(2-hydroxy-5-methylphenyl)benzotriazole,2-(2-hydroxy-5-tert-octylphenyl)-benzotriazole and 2-hydroxy-4-n-octoxybenzophenone, or the like, or combinations comprising at least one ofthe foregoing light stabilizers. Light stabilizers are generally used inamounts of 0.0001 to 1 parts by weight, based on 100 parts by weight ofthe polymer component of the thermoplastic composition.

Exemplary UV absorbing additives include for example,hydroxybenzophenones; hydroxybenzotriazoles; hydroxybenzotriazines;cyanoacrylates; oxanilides; benzoxazinones;2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (CYASORB®5411); 2-hydroxy-4-n-octyloxybenzophenone (CYASORB® 531);2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)-phenol(CYASORB® 1164); 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one)(CYASORB® UV-3638);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane (UVINUL® 3030);2,2′-(1,4-phenylene) bis(4H-3,1-benzoxazin-4-one);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane;nano-size inorganic materials such as titanium oxide, cerium oxide, andzinc oxide, all with particle size less than or equal to 100 nanometers;or the like, or combinations comprising at least one of the foregoing UVabsorbers. UV absorbers are generally used in amounts of 0.0001 to 1part by weight, based on 100 parts by weight of the polymer component ofthe thermoplastic composition.

Plasticizers, lubricants, and/or mold release agents can also be used.There is considerable overlap among these types of materials, whichinclude, for example, phthalic acid esters such asdioctyl-4,5-epoxy-hexahydrophthalate;tris-(octoxycarbonylethyl)isocyanurate; tristearin; di- orpolyfunctional aromatic phosphates such as resorcinol tetraphenyldiphosphate (RDP), the bis(diphenyl) phosphate of hydroquinone and thebis(diphenyl) phosphate of bisphenol-A; poly-alpha-olefins; epoxidizedsoybean oil; silicones, including silicone oils; esters, for example,fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate,stearyl stearate, pentaerythritol tetrastearate (PETS), and the like;combinations of methyl stearate and hydrophilic and hydrophobic nonionicsurfactants comprising polyethylene glycol polymers, polypropyleneglycol polymers, poly(ethylene glycol-co-propylene glycol) copolymers,or a combination comprising at least one of the foregoing glycolpolymers, e.g., methyl stearate and polyethylene-polypropylene glycolcopolymer in a suitable solvent; waxes such as beeswax, montan wax,paraffin wax, or the like. Such materials are generally used in amountsof 0.001 to 1 part by weight, specifically 0.01 to 0.75 parts by weight,more specifically 0.1 to 0.5 parts by weight, based on 100 parts byweight of the polymer component of the thermoplastic composition.

The term “antistatic agent” refers to monomeric, oligomeric, orpolymeric materials that can be processed into polymer resins and/orsprayed onto materials or articles to improve conductive properties andoverall physical performance Examples of monomeric antistatic agentsinclude glycerol monostearate, glycerol distearate, glyceroltristearate, ethoxylated amines, primary, secondary and tertiary amines,ethoxylated alcohols, alkyl sulfates, alkylarylsulfates,alkylphosphates, alkylaminesulfates, alkyl sulfonate salts such assodium stearyl sulfonate, sodium dodecylbenzenesulfonate or the like,quaternary ammonium salts, quaternary ammonium resins, imidazolinederivatives, sorbitan esters, ethanolamides, betaines, or the like, orcombinations comprising at least one of the foregoing monomericantistatic agents.

Exemplary polymeric antistatic agents include certain polyesteramidespolyether-polyamide (polyetheramide) block copolymers,polyetheresteramide block copolymers, polyetheresters, or polyurethanes,each containing polyalkylene glycol moieties polyalkylene oxide unitssuch as polyethylene glycol, polypropylene glycol, polytetramethyleneglycol, and the like. Such polymeric antistatic agents are commerciallyavailable, for example PELESTAT® 6321 (Sanyo) or PEBAX® MH1657(Atofina), IRGASTAT® P18 and P22 (Ciba-Geigy). Other polymeric materialsthat can be used as antistatic agents are inherently conducting polymerssuch as polyaniline (commercially available as PANIPOL® EB fromPanipol), polypyrrole and polythiophene (commercially available fromBayer), which retain some of their intrinsic conductivity after meltprocessing at elevated temperatures. In one embodiment, carbon fibers,carbon nanofibers, carbon nanotubes, carbon black, or a combinationcomprising at least one of the foregoing can be used in a polymericresin containing chemical antistatic agents to render the compositionelectrostatically dissipative. Antistatic agents are generally used inamounts of 0.0001 to 5 parts by weight, based on 100 parts by weight ofthe polymer component of the thermoplastic composition.

Colorants such as pigment and/or dye additives can also be presentprovided they do not adversely affect flame retardant performance.Useful pigments can include, for example, inorganic pigments such asmetal oxides and mixed metal oxides such as zinc oxide, titaniumdioxides, iron oxides, or the like; sulfides such as zinc sulfides, orthe like; aluminates; sodium sulfo-silicates sulfates, chromates, or thelike; carbon blacks; zinc ferrites; ultramarine blue; organic pigmentssuch as azos, di-azos, quinacridones, perylenes, naphthalenetetracarboxylic acids, flavanthrones, isoindolinones,tetrachloroisoindolinones, anthraquinones, enthrones, dioxazines,phthalocyanines, and azo lakes; Pigment Red 101, Pigment Red 122,Pigment Red 149, Pigment Red 177, Pigment Red 179, Pigment Red 202,Pigment Violet 29, Pigment Blue 15, Pigment Blue 60, Pigment Green 7,Pigment Yellow 119, Pigment Yellow 147, Pigment Yellow 150, and PigmentBrown 24; or combinations comprising at least one of the foregoingpigments. Pigments are generally used in amounts of 0.01 to 10 parts byweight, based on 100 parts by weight of the polymer component of thethermoplastic composition.

Exemplary dyes are generally organic materials and include, for example,coumarin dyes such as coumarin 460 (blue), coumarin 6 (green), nile redor the like; lanthanide complexes; hydrocarbon and substitutedhydrocarbon dyes; polycyclic aromatic hydrocarbon dyes; scintillationdyes such as oxazole or oxadiazole dyes; aryl- or heteroaryl-substitutedpoly (C2-8) olefin dyes; carbocyanine dyes; indanthrone dyes;phthalocyanine dyes; oxazine dyes; carbostyryl dyes;napthalenetetracarboxylic acid dyes; porphyrin dyes; bis(styryl)biphenyldyes; acridine dyes; anthraquinone dyes; cyanine dyes; methine dyes;arylmethane dyes; azo dyes; indigoid dyes, thioindigoid dyes, diazoniumdyes; nitro dyes; quinone imine dyes; aminoketone dyes; tetrazoliumdyes; thiazole dyes; perylene dyes, perinone dyes;bis-benzoxazolylthiophene (BBOT); triarylmethane dyes; xanthene dyes;thioxanthene dyes; naphthalimide dyes; lactone dyes; fluorophores suchas anti-stokes shift dyes which absorb in the near infrared wavelengthand emit in the visible wavelength, or the like; luminescent dyes suchas 7-amino-4-methylcoumarin;3-(2′-benzothiazolyl)-7-diethylaminocoumarin;2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole;2,5-bis-(4-biphenylyl)-oxazole; 2,2′-dimethyl-p-quaterphenyl;2,2-dimethyl-p-terphenyl; 3,5,3″″,5″″-tetra-t-butyl-p-quinquephenyl;2,5-diphenylfuran; 2,5-diphenyloxazole; 4,4′-diphenylstilbene;4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran;1,1′-diethyl-2,2′-carbocyanine iodide;3,3′-diethyl-4,4′,5,5′-dibenzothiatricarbocyanine iodide;7-dimethylamino-1-methyl-4-methoxy-8-azaquinolone-2;7-dimethylamino-4-methylquinolone-2;2-(4-(4-dimethylaminophenyl)-1,3-butadienyl)-3-ethylbenzothiazoliumperchlorate; 3-diethylamino-7-diethyliminophenoxazonium perchlorate;2-(1-naphthyl)-5-phenyloxazole; 2,2′-p-phenylen-bis(5-phenyloxazole);rhodamine 700; rhodamine 800; pyrene, chrysene, rubrene, coronene, orthe like; or combinations comprising at least one of the foregoing dyes.Dyes are generally used in amounts of 0.01 to 10 parts by weight, basedon 100 parts by weight of the polymer component of the thermoplasticcomposition.

Where a foam is desired, useful blowing agents include, for example, lowboiling halohydrocarbons and those that generate carbon dioxide; blowingagents that are solid at room temperature and when heated totemperatures higher than their decomposition temperature, generate gasessuch as nitrogen, carbon dioxide, and ammonia gas, such asazodicarbonamide, metal salts of azodicarbonamide, 4,4′oxybis(benzenesulfonylhydrazide), sodium bicarbonate, ammoniumcarbonate, or the like, or combinations comprising at least one of theforegoing blowing agents. Blowing agents are generally used in amountsof 0.01 to 20 parts by weight, based on 100 parts by weight of thepolymer component of the thermoplastic composition.

Anti-drip agents can also be used in the thermoplastic composition, forexample a fibril forming or non-fibril forming fluoropolymer such aspolytetrafluoroethylene (PTFE). The anti-drip agent can be encapsulatedby a rigid copolymer as described above, for examplestyrene-acrylonitrile copolymer (SAN). PTFE encapsulated in SAN is knownas TSAN. Encapsulated fluoropolymers can be made by polymerizing theencapsulating polymer in the presence of the fluoropolymer, for examplean aqueous dispersion. TSAN can provide significant advantages overPTFE, in that TSAN can be more readily dispersed in the composition. Anexemplary TSAN can comprise 50 wt. % PTFE and 50 wt. % SAN, based on thetotal weight of the encapsulated fluoropolymer. The SAN can comprise,for example, 75 wt. % styrene and 25 wt. % acrylonitrile based on thetotal weight of the copolymer. Alternatively, the fluoropolymer can bepre-blended in some manner with a second polymer, such as for, example,an aromatic polycarbonate or SAN to form an agglomerated material foruse as an anti-drip agent. Either method can be used to produce anencapsulated fluoropolymer. Antidrip agents are generally used inamounts of 0.1 to 5 percent by weight, based on 100 parts by weight ofthe polymer component of the thermoplastic composition.

Radiation stabilizers can also be present, specifically gamma-radiationstabilizers. Exemplary gamma-radiation stabilizers include alkylenepolyols such as ethylene glycol, propylene glycol, 1,3-propanediol,1,2-butanediol, 1,4-butanediol, meso-2,3-butanediol, 1,2-pentanediol,2,3-pentanediol, 1,4-pentanediol, 1,4-hexandiol, and the like;cycloalkylene polyols such as 1,2-cyclopentanediol, 1,2-cyclohexanediol,and the like; branched alkylenepolyols such as2,3-dimethyl-2,3-butanediol (pinacol), and the like, as well asalkoxy-substituted cyclic or acyclic alkanes. Unsaturated alkenols arealso useful, examples of which include 4-methyl-4-penten-2-ol,3-methyl-pentene-3-ol, 2-methyl-4-penten-2-ol, 2,4-dimethyl-4-pene-2-ol,and 9 to decen-1-ol, as well as tertiary alcohols that have at least onehydroxy substituted tertiary carbon, for example2-methyl-2,4-pentanediol (hexylene glycol), 2-phenyl-2-butanol,3-hydroxy-3-methyl-2-butanone, 2-phenyl-2-butanol, and the like, andcyclic tertiary alcohols such as 1-hydroxy-1-methyl-cyclohexane. Certainhydroxymethyl aromatic compounds that have hydroxy substitution on asaturated carbon attached to an unsaturated carbon in an aromatic ringcan also be used. The hydroxy-substituted saturated carbon can be amethylol group (—CH2OH) or it can be a member of a more complexhydrocarbon group such as —CR4HOH or —CR24OH wherein R4 is a complex ora simple hydrocarbon. Specific hydroxy methyl aromatic compounds includebenzhydrol, 1,3-benzenedimethanol, benzyl alcohol, 4-benzyloxy benzylalcohol and benzyl benzyl alcohol. 2-Methyl-2,4-pentanediol,polyethylene glycol, and polypropylene glycol are often used forgamma-radiation stabilization. Gamma-radiation stabilizing compounds aretypically used in amounts of 0.1 to 10 parts by weight based on 100parts by weight of the polymer component of the thermoplasticcomposition.

Thermoplastic compositions comprising the endcapped polycarbonates andflame retardants can be manufactured by various methods. For example,endcapped polycarbonate, flame retardant, impact modifier (if present),and/or other optional components are first blended in a HENSCHEL-Mixer®high speed mixer. Other low shear processes, including but not limitedto hand mixing, can also accomplish this blending. The blend is then fedinto the throat of a single or twin-screw extruder via a hopper.Alternatively, at least one of the components can be incorporated intothe composition by feeding directly into the extruder at the throatand/or downstream through a sidestuffer. Additives can also becompounded into a masterbatch with a desired polymeric resin and fedinto the extruder. The extruder is generally operated at a temperaturehigher than that necessary to cause the composition to flow. Theextrudate is immediately quenched in a water batch and pelletized. Thepellets, so prepared, when cutting the extrudate can be one-fourth inchlong or less as desired. Such pellets can be used for subsequentmolding, shaping, or forming.

In some embodiments described above, the onset of high-temperaturecross-linking can be controlled by adjusting the molecular weight of theendcapped polycarbonate or by the addition of certain flame retardantsalts, in particular alkali metal salts of perfluorinated C1-16 alkylsulfonates. In one embodiment, the addition of an inorganic flameretardant (e.g., KSS) increases the temperature of the onset ofcross-linking/branching in the polycarbonate by 20 to 80° C.,specifically 40 to 60° C.

Shaped, formed, or molded articles comprising the thermoplasticcompositions are also provided. The thermoplastic compositions can bemolded into useful shaped articles by a variety of means such asinjection molding, extrusion, rotational molding, blow molding andthermoforming to form articles such as, for example, computer andbusiness machine housings such as housings for monitors, handheldelectronic device housings such as housings for cell phones, electricalconnectors, and components of lighting fixtures, ornaments, homeappliances, roofs, greenhouses, sun rooms, swimming pool enclosures, andthe like. The compositions are of particular utility in the manufactureof thin walled articles such as housings for electronic devices.Additional examples of articles that can be formed from the compositionsinclude electrical parts, such as relays, and enclosures, consumerelectronics such as enclosures and parts for laptops, desktops, dockingstations, PDAs, digital cameras, desktops, and telecommunications partssuch as parts for base station terminals.

E. Polycarbonate Synthesis Processes

Polycarbonates can be manufactured by processes such as interfacialpolymerization or melt polymerization. Although the reaction conditionsfor interfacial polymerization can vary, an exemplary process generallyinvolves dissolving or dispersing a dihydric phenol reactant in aqueouscaustic soda or potash, adding the resulting mixture to awater-immiscible solvent medium, and contacting the reactants with acarbonate precursor in the presence of a catalyst such as, for example,triethylamine or a phase transfer catalyst, under controlled pHconditions, e.g., 8 to 11. The most commonly used water immisciblesolvents include methylene chloride, 1,2-dichloroethane, chlorobenzene,toluene, and the like.

Exemplary carbonate precursors include, for example, a carbonyl halidesuch as carbonyl bromide or carbonyl chloride, or a haloformate such asa bishaloformates of a dihydric phenol (e.g., the bischloroformates ofbisphenol A, hydroquinone, or the like) or a glycol (e.g., thebishaloformate of ethylene glycol, neopentyl glycol, polyethyleneglycol, or the like). Combinations comprising at least one of theforegoing types of carbonate precursors can also be used. In anexemplary embodiment, an interfacial polymerization reaction to formcarbonate linkages uses phosgene as a carbonate precursor, and isreferred to as a phosgenation reaction.

Among the phase transfer catalysts that can be used are catalysts of theformula (R³)₄Q⁺X, wherein each R³ is the same or different, and is aC₁₋₁₀ alkyl group; Q is a nitrogen or phosphorus atom; and X is ahalogen atom or a C₁₋₈ alkoxy group or C₆₋₁₈ aryloxy group. Exemplaryphase transfer catalysts include, for example, [CH₃(CH₂)₃]₄NX,[CH₃(CH₂)₃]₄PX, [CH₃(CH₂)₅]₄NX, [CH₃(CH₂)₆]₄NX, [CH₃(CH₂)₄]₄NX,CH₃[CH₃(CH₂)₃]₃NX, and CH₃[CH₃(CH₂)₂]₃NX, wherein X is Cl⁻, Br⁻, a C₁₋₈alkoxy group or a C₆₋₁₈ aryloxy group. An effective amount of a phasetransfer catalyst can be 0.1 to 10 wt. % based on the weight ofbisphenol in the phosgenation mixture. In another embodiment aneffective amount of phase transfer catalyst can be 0.5 to 2 wt. % basedon the weight of bisphenol in the phosgenation mixture.

Alternatively, melt processes can be used to make the endcappedpolycarbonates. Generally, in the melt polymerization process,polycarbonates can be prepared by co-reacting, in a molten state, thedihydroxy reactant(s) and a diaryl carbonate ester, such as diphenylcarbonate, in the presence of a transesterification catalyst in aBanbury® mixer, twin screw extruder, or the like to form a uniformdispersion. Volatile monohydric phenol is removed from the moltenreactants by distillation and the polymer is isolated as a moltenresidue. A specifically useful melt process for making polycarbonatesuses a diaryl carbonate ester having electron-withdrawing substituentson the aryls. Examples of specifically useful diaryl carbonate esterswith electron withdrawing substituents includebis(4-nitrophenyl)carbonate, bis(2-chlorophenyl)carbonate,bis(4-chlorophenyl)carbonate, bis(methyl salicyl)carbonate,bis(4-methylcarboxylphenyl) carbonate, bis(2-acetylphenyl) carboxylate,bis(4-acetylphenyl) carboxylate, or a combination comprising at leastone of the foregoing.

It is believed that the foregoing amendments fully comply with theNotice to File Corrected Application Papers. Accordingly,reconsideration and withdrawal of the objection is respectfullyrequested.

If there are any additional charges with respect to this Amendment orotherwise, please charge them to Deposit Account No. 06-1130.

Exemplary transesterification catalysts for making polycarbonate using amelt process include acetates, carbonates, borates, borohydrides,oxides, hydroxides, hydrides, and alcoholates of various metalsincluding alkali metals such as lithium, sodium, and potassium, alkaliearth metals such as magnesium, calcium and barium and other metals suchas zinc, cadmium, tin, antimony, lead, manganese cobalt, or nickel. Inaddition, other useful transesterification catalysts include basic saltsof nitrogen or phosphorus such as tetrabutylammonium hydroxide,methyltributylammonium hydroxide, tetrabutylammonium acetate,tetrabutylphosphonium hydroxide, tetrabutylphosphonium acetate,tetrabutylphosphonium phenolate. Combinations of at least one of theforegoing are also useful.

Protocols may be adjusted so as to obtain a desired product within thescope of this disclosure and this can be done without undueexperimentation. The desired product is in one embodiment is to achievea molded article of the composition has a UL 94 V0 rating at a thicknessof 1 mm, 1.5 mm, 2.0 mm, or between about 1.0 mm and about 2.0 mm.

In one embodiment, the invention provides a method of making an articleof manufacture that has a V0 94 rating at a thickness of between 1.5 and2 mm: (a) providing a polycarbonate, wherein the polycarbonate has arepeating structural background of the following formula

wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups; an end capping agent; a branching agent;(b) selecting the end-capping agent based upon the molecular weight ofsaid polycarbonate and said branching level imparted by said branchingagent, wherein the MVR of the polycarbonate is from about 1 to about 15cubic cm/10 min and wherein the pKa of the end-capping agent is fromabout 8.3 to about 11; (c) forming a polycarbonate containing saidend-capping agent and said branching that has a peak melt viscosity ofat least 8,000 poise when measured using a parallel plate melt rheologytest at a heating rate of 10° C./min at a temperature of between about350° C. and about 450° C.; and (d) blending a flame retardant with saidformed polycarbonate.

In a further embodiment, the peak melt viscosity is at least 25,000poise when measured using a parallel plate melt rheology test at aheating rate of 10° C./min at a temperature of between about 350° C. toabout 450° C.

In yet another embodiment, the pKa of the end-capping agent is fromabout 8.3 to about 11.

F. Performance Properties

Achieving excellent flame performance, (UL 94 V0) for thin wall articles(e.g. 2 mm and thinner) made from polycarbonate resins requiresachieving short flame out times while preventing flaming drips during UL94 testing. Short flame out times are usually achieved through the useof flame retardant agents while flaming drips are prevented by addinganti-drip agents such as polytetrafluoroethylene (PTFE). In addition,achieving excellent flame performance for transparent thin wall articlesis particularly challenging because anti-drip agents such as PTFE renderthe article translucent or opaque. Therefore preventing dripping has tobe achieved by other means for transparent thin wall articles.

One way to reduce dripping is to increase the molecular weight of thepolycarbonate resin but this approach reduces the flow of the resinduring molding and so thin wall molds having long flow lengths orintricate designs are difficult to fill without increasing the moldingtemperature and risking polycarbonate molecular weight degradation andcolor formation. Branched polycarbonate resins can provide a partialsolution to the flow problem because branching provides a means for thepolycarbonate chains to entangle, thus reducing dripping without loosingas much flow during molding. However branched polycarbonates with higherlevels of branching (1% branching or above) can be difficult to makebecause when the branching is too high the polycarbonates form gels inthe manufacturing process and sometimes during molding. Gels hurt theimpact properties and the aesthetics of transparent polycarbonatearticles and so highly branched polycarbonates are generally avoided inpolycarbonate manufacture and in product formulations.

A certain type of end-group, e.g. p-cyanophenol, attached to the ends ofbranched polycarbonate chains can also provide anti-dripping benefitsduring UL testing. Not all branched polycarbonates are formed fromp-cyanophenol end-capping agents however.

A general way has been discovered to design polycarbonates by balancingmolecular weight, branching level and end-group type to producetransparent polycarbonate formulations that are easily molded into thinwall articles and pass UL 94 V0 testing. This involves measuring thepeak melt viscosity of the polycarbonate between 350° C. and 450° C.during a melt rheology test. The “peak melt viscosity” is the highestmelt viscosity value (in poise) achieved between 350° C. and 450° C.during rheological testing of a polycarbonate resin.

It has been found that when the peak melt viscosity of a polycarbonateresin containing said branching agent and said end-capping agent is ator above 25,000 poise between 350° C. and 450° C., a molded article madefrom that resin and a flame retardant additive, consistently passes ULV0 testing at 1.0 mm thickness or above. A polycarbonate resin having apeak melt viscosity of 7,000 poise between 350° C. and 450° C., whenformulated with a flame retardant additive, provides a molded articlethat consistent passes UL V0 testing at 1.5 mm thickness or above.

Furthermore after measuring the peak melt viscosity of manypolycarbonate resins having different levels of branching, MW (weightaverage molecular weight of the polycarbonate containing saidend-capping agent and said branching agent) and different types ofend-capping agents a relationship has been discovered between thebranching level, BL (moles branching agent/moles bisphenol(s)), MW (byGPC using polycarbonate standards) and pKa of the end-capping agent.This relationship is expressed in the following polynomial equation:Peak MeltViscosity=−57135.91+36961.39*BL+14001.13*MW^(1/3)−46944.24*pKa−322.51*BL*MW^(1/3)−2669.19*BL*pKa+215.83*MW^(1/3)*pKa+1125.63*BL²−200.11*MW^(2/3)+2231.15*pKa²wherein BL is the mole ratio of branching agent in the formulationdetermined by dividing the number of moles of branching agent by thetotal number of moles of bisphenol or bisphenols in the composition, theMW is the weight-averaged molecular weight of the polycarbonatecontaining said branching agent and said end-capping agent as determinedby gel permeation chromatography using polycarbonate standards, and thepKa is the pKa of the end capping agent.

The equation above allows the design of a wide range of polycarbonateresins that will pass UL 94 V0 testing at thin wall thicknesses.Designing the polycarbonate resins involves selecting an end-cappingagent and adjusting the MW of the resin and the branching level of theresin in the manufacturing process so that the calculated or measuredpeak melt viscosity, e.g. has a high value 7000 poise or greater for 1.5mm or greater and 25,000 poise or greater for 1.0 mm or greater. If thepKa of the end-capping agent has a low value (for examplemethyl-p-hydroxy benzoate with a pKA of 8) the MW and the amountbranching level needed to achieve a UL V0 performance can be lower. Ifthe pKa of the end-capping agent is higher (for example p-t-butylphenolwith a pKa of 10.3) then the MW and the branching level will need to behigher. Furthermore after the end-capping agent is selected, a choicecan be made between balancing the molecular weight with the level ofbranching agent in the manufacturing process. The balance between thefactors can be done without undue experimentation.

Without being bound by theory the viscosity behavior of thepolycarbonate resin containing said branching agent and said end-cappingagent as it passes through the temperature range between 350° C. and450° C. reflects the beginning of the building up of a polymeric networkthat impacts the dripping behavior of the resin during UL 94 flametesting. Polycarbonate resins that build this network to a higher degree(reflected in a higher peak melt viscosity value in the rheologicaltest) seem to perform better in the UL flame testing at thin walls. Thehigher the value of the peak melt viscosity the thinner the wallthickness can be for a UL 94 V0 pass.

Surprisingly blending of the polycarbonates with high peak meltviscosities with other polycarbonates also provides blends withexcellent flow properties and good FR performance at thin wallthicknesses. The most effective polycarbonates for blending are thosepolycarbonates that have measured peak measured melt viscosities of25,000 Poise or a calculated peak melt viscosities of 25,000 Poise orgreater. Thus, in one embodiment, a polycarbonate having aweight-averaged MW of 35,526 g/mole and a calculated peak melt viscosityof 23,923 Poise was blended with a second polycarbonate having aweight-average MW of 22,999 g/mole in a 1:1 ratio Rimar Salt flameretardant, octaphenylcyclotetrasiloxane, a heat stabilizer and a moldrelease agent were also present in the blend. The blend had an MVR of13.8 (300° C./1.2 kg, 360 s). The blend showed UL-94 V0 rating at 1.5 mmthickness.

In one embodiment, the present invention further provides for acomposition comprising: a flame retardant; a polycarbonate, wherein thepolycarbonate has a repeating structural background of the followingformula

wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups and wherein the polycarbonate contains oneor more bisphenols; wherein the polycarbonate comprises an end-cappingagent that is not cyanophenol; wherein the polycarbonate comprises abranching agent; and wherein the polycarbonate containing said branchingagent and said end-capping agent has a peak melt viscosity of at least7,000 poise when calculated from the equation of wherein said peak meltviscosity equals:−57135.91+36961.39*BL+14001.13*MW^(1/3)−46944.24*pKa−322.51*BL*MW^(1/3)−2669.19*BL*pKa+215.83*MW^(1/3)*pKa+1125.63*BL²−200.11*MW^(2/3)+2231.15*pKa²,wherein BL is the mole ratio of the branching agent in the formulationdetermined by dividing the number of moles of branching agent by thetotal number of moles of bisphenol or bisphenols in the composition, theMW is the weight-averaged molecular weight of said polycarbonatecontaining said branching agent and said end-capping agent as determinedby gel permeation chromatography using polycarbonate standards, and thepKa is the pKa of the end capping agent; and wherein a molded article ofthe composition has a UL 94 V0 rating at a thickness of 1 mm, 1.5 mm,2.0 mm, or between about 1.0 mm and about 2.0 mm.

In a further embodiment, the peak melt viscosity is at least 25,000 ascalculated by the above equation.

In another embodiment, the present invention further provides for amethod of making an article of manufacture that has a V0 94 rating at athickness of between 1.5 mm and 2 mm: (a) providing a polycarbonate,wherein the polycarbonate has a repeating structural background of thefollowing formula

wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups and wherein the polycarbonate contains oneor more bisphenols; an end capping agent that is not cyanophenol; abranching agent; (b) selecting the end-capping agent based upon themolecular weight of said polycarbonate and said branching level impartedby said branching agent, wherein the MVR of the polycarbonate is fromabout 1 to about 15 cubic cm/10 min and wherein the pKa of theend-capping agent is from about 8 to about 11; (c) forming apolycarbonate containing said end-capping agent and said branching agentthat has a peak melt viscosity that is at least 7,000 poise whencalculated from the equation of wherein said peak melt viscosity equals:−57135.91+36961.39*BL+14001.13*MW^(1/3)−46944.24*pKa−322.51*BL*MW^(1/3)−2669.19*BL*pKa+215.83*MW^(1/3)*pKa+1125.63*BL²-200.11*MW^(2/3)+2231.15*pKa²;and wherein BL is the mole ratio of the branching agent in theformulation determined by dividing the number of moles of branchingagent by the total number of moles of bisphenol or bisphenols in thecomposition, the MW is the weight-averaged molecular weight of saidformed polycarbonate as determined by gel permeation chromatographyusing polycarbonate standards, and the pKa is the pKa of the end cappingagent; and (d) blending a flame retardant with said formedpolycarbonate.

In a further embodiment, the peak melt viscosity is at least 25,000poise calculated from the above equation.

A thin wall article with a good flame-retardance performance is anobjective of the claimed disclosure. One way of determining whether acomposition of matter has good flame retardant properties is by lookingat its UL 94 rating.

In one embodiment, a molded article of the composition has a UL 94 V0rating at a thickness of 1.5 mm, 2.0 mm, or between 1.0 mm and 2.0 mm.

In another embodiment, a molded article of the composition has a UL 94V0 rating at a thickness of 2 mm.

In another embodiment, a molded article of the composition has a UL 94V0 rating at a thickness of 1.5 mm.

In another embodiment, a molded article of the composition has a UL 94V0 rating at a thickness of 1.0 mm.

In another embodiment, a molded article of the composition has a UL 94V0 rating at a thickness of between 1.0 mm and 2.0 mm.

Melt volume flow rate (often abbreviated “MVR”) measures the rate ofextrusion of a thermoplastic through an orifice at a prescribedtemperature and load. The endcapped polycarbonates can have an MVR,measured at 300° C. under a load of 1.2 kg, of 0.1 to 200 cubiccentimeters per 10 minutes (cm³/10 min), specifically 1 to 100 cm³/10min MVR was measured by ASTM D 1238.

In one embodiment, the polycarbonate has an MVR of at least about 3cubic cm/10 min. In a further embodiment, the polycarbonate has an MVRof about 3 to about 30 or about 3 to about 10 cubic cm/10 min or fromabout 1 to about 15 cubic cm/10 min.

The following polycarbonates encompassed by the claimedinvention/disclosure have various haze levels.

In one embodiment, the composition has a haze value of less than 1.5% at3.2 mm thickness by ASTM D1003.

The molecular weight of the polycarbonate containing said branching andsaid end-capping agent may vary depending on various end uses or otherperformance properties.

In one embodiment, the polycarbonate containing said branching agent andend-capping agent is between 20,000 g/mol to 40,000 instead g/mol asmeasured by gel permeation chromatography using polycarbonate standards.

The following embodiments are also encompassed by the claimed invention.

In one embodiment, the composition A composition comprising: a flameretardant; a polycarbonate, wherein the polycarbonate has a repeatingstructural background of the following formula

wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups; wherein the polycarbonate comprises anend capping agent selected from phenol, or a phenol substituted with oneor more alkyl groups, alkoxy groups, ester groups, ether groups orhalogens; wherein the polycarbonate comprises a branching agent selectedfrom at least one of the following THPE, TMTC, and isatin-bis-phenol;wherein the branching level of said polycarbonate is at least about 1%;wherein the molecular weight of said polycarbonate is about 20,000g/mole to about 40,000 g/mole; wherein the pKa of said end-capping agentis between about 8.3 and about 11; wherein the flame retardant includesa potassium perfluorobutane sulfonate salt and optionally excludes achlorine or bromine containing composition; wherein the polycarbonatecontaining said branching agent and said end-capping agent has a peakmelt viscosity of at least 8,000 poise when measured using a parallelplate melt rheology test at a heating rate of 10° C./min at atemperature of between about 350° C. and about 450° C.; and wherein amolded article of the composition has a UL 94 V0 rating at a thicknessof 1.0, 1.5 mm, 2.0 mm, or between 1.0 mm and 2.0 mm

In a further embodiment, the polycarbonate is derived from bisphenol-A.

In yet a further embodiment, the composition comprises a secondpolycarbonate that is different from the polycarbonate and wherein saidsecond polycarbonate comprises a repeating structure of

wherein said second polycarbonate is different from said polycarbonateand wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups.

In yet a further embodiment, the second polycarbonate is bisphenol-Apolycarbonate.

In another embodiment, a flame retardant that contains a potassiumperfluorobutane sulfonate salt greater than about 0.04 wt. % based uponthe total weight of polycarbonate resin in the composition; apolycarbonate, wherein the polycarbonate has a repeating structuralbackground of the following formula

wherein at least 60 percent of the total number of R¹ groups containaromatic organic groups and the balance thereof are aliphatic,alicyclic, or aromatic groups; wherein the polycarbonate comprises anend-capping agent that is not cyanophenol; wherein the polycarbonatecomprises a branching agent; wherein the polycarbonate containing saidbranching agent and said end-capping agent is between 20,000 g/mol and40,000 g/mol;wherein the MVR of the polycarbonate is from about 3 to about 10 cubiccm/10 min; wherein said branching agent provides a level of branchingbetween about 1% and about 3%; wherein the pKa of the end-capping agentis between about 8.3 and about 10.2; wherein the polycarbonatecontaining said branching agent and said end-capping agent has a peakmelt viscosity of at least 8,000 poise or at least 25,000 poise whenmeasured using a parallel plate melt rheology test at a heating rate of10° C./min at a temperature of between about 350° C. to about 450° C.;wherein a molded article of the composition has a UL 94 V0 rating at athickness of 1 mm, 1.5 mm, 2.0 mm, or between 1.0 mm and 2.0 mm; andwherein the haze of the molded article is less than 1.5% at 3.2 mmthickness by ASTM D1003.

All thermoplastic compositions except where indicated were compounded ona Werner & Pfleiderer co-rotating twin screw extruder (Length/Diameter(L/D) ratio=30/1, vacuum port located near die face), with enoughdistributive and dispersive mixing elements to produce good mixingbetween the components of the polymer compositions. The compositionswere subsequently molded according to ISO 294 on a Husky or BOYinjection-molding machine. Compositions were compounded and molded at atemperature of 270 to 330° C., although it will be recognized by oneskilled in the art that the method is not be limited to thesetemperatures.

Ranges articulated within this disclosure, e.g. numerics/values, shallinclude disclosure for possession purposes and claim purposes of theindividual points within the range, sub-ranges, and combinationsthereof.

Various combinations of elements of this disclosure are encompassed bythis invention, e.g. combinations of elements from dependent claims thatdepend upon the same independent claim.

The invention is further illustrated by the following non-limitingexamples.

Examples A1. Testing Procedure & Description of Testing Components

Different composition of flame-retarded additives and PC are mixedtogether and pre-blended. Extrusion and molding is carried out undernormal polycarbonate processing condition.

Flammability testing was conducted using the standard UnderwritersLaboratory UL 94 test method (7 day conditioning), except that 20 barsrather than the usual 5 bars were tested. Specimens are to bepreconditioned in an air-circulating oven for 168 hours at 70+/−1° C.and then cooled in the desiccator for at least 4 hours at roomtemperature, prior to testing. Once removed from the desiccator,specimens shall be tested within 30 minutes. The data was analyzed bycalculation of the average flame out time, standard deviation of theflame out time and the total number of drips. Statistical methods wereused to convert the data to a probability that a specific formulationwould achieve a first time V0 pass or “p(FTP)” in the standard UL 94testing of 5 bars. Preferably p(FTP) values will be 1 or very close to 1for high confidence that a sample formulation would achieve a V0 ratingin UL 94 testing. A p(FTP) value below 0.85 for a sample formulation wasconsidered too low to predict a UL 94 rating of V0 for that formulation.

Peak Melt Viscosity values on resin samples were obtained on a dynamicrheometer using a Rheometrics ARES with a parallel plate fixture at aheating rate at 10° C./min at a frequency of 3 rad/s and strainamplitude of 9% and heated by hot air. The Peak Melt Viscosity wasdetermined from a graph of the melt viscosity change as a function oftemperature during the rheometric test. The highest absolute meltviscosity value (in Poise) on the graph between the temperatures of 350°C. (after polymer softening) to 450° C. (before polymer degradation) wasdefined as the Peak Melt Viscosity (see FIG. 1).

Molecular Weight values were by gel permeation chromatography (GPC),using a crosslinked styrene-divinylbenzene column and calibrated topolycarbonate references. GPC samples are prepared at a concentration ofabout 1 mg/ml, and are eluted at a flow rate of about 1.5 ml/min usingmethylene chloride as the solvent.

Flammability tests were performed following the procedure ofUnderwriter's Laboratory Bulletin 94 entitled “Tests for Flammability ofPlastic Materials, UL94.” Several ratings can be applied based on therate of burning, time to extinguish, ability to resist dripping, andwhether or not drips are burning. According to this procedure, materialscan be classified as UL94 HB, V0, V1, V2, on the basis of the testresults obtained for five samples. The criteria for each of theseflammability classifications are described below. HB: In a 5-inchsample, placed so that the long axis of the sample is horizontal to theflame, the rate of burn of the sample is less than 3 inches per minute,and the flame is extinguished before 4 inches of sample are burned.

V0: In a sample placed so that its long axis is 180 degrees to theflame, the average period of flaming and/or smoldering after removingthe igniting flame does not exceed ten seconds and none of thevertically placed samples produces drips of burning particles thatignite absorbent cotton. Five bar flame out time (FOT) is the sum of theflame out time for five bars, each lit twice for a maximum flame outtime of 50 seconds.V1: In a sample placed so that its long axis is 180 degrees to theflame, the average period of flaming and/or smoldering after removingthe igniting flame does not exceed twenty-five seconds and none of thevertically placed samples produces drips of burning particles thatignite absorbent cotton. Five bar flame out time is the sum of the flameout time for five bars, each lit twice for a maximum flame out time of250 seconds.V2: In a sample placed so that its long axis is 180 degrees to theflame, the average period of flaming and/or smoldering after removingthe igniting flame does not exceed twenty-five seconds, but thevertically placed samples produce drips of burning particles that ignitecotton. Five bar flame out time is the sum of the flame out time forfive bars, each lit twice for a maximum flame out time of 250 seconds.

B1. General Method for Preparing Polycarbonate Samples with HighBranching Contents and Different End Capping Agents

The experimental method described below illustrates the procedure formaking a polycarbonate containing approximately 1% THPE branching leveland using methyl-p-hydroxybenzoate as the end-capping agent.

The following were added into a 70 L CSTR (continuous stirred reactor)equipped with an overhead condenser and a recirculation pump with a flowrate of 40 L/minute: (a) 4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4500g, 19.73 mol); (b) methyl p-hydroxybenzoate (135 g, 0.89 mol);1,1,1-tris(4-hydroxyphenyl)ethane (THPE, 63 g, 0.2 mol); (c)triethylamine (20 mL, 0.197 mol); (d) methylene chloride (24.3 L); (e)de-ionized water (10.7 L), and (f) sodium gluconate (10 g). The reactionwas allowed to stir for 10 minutes and the pH was maintained between 8and 9 by the addition of 30 wt. % NaOH solution. The mixture was chargedwith phosgene (2708.1 g, 80 g/min, 27.37 mol). During the addition ofphosgene, base (30 wt. % NaOH in deionized water) was simultaneouslycharged to the reactor to maintain the pH of the reaction between 9 and10. After the complete addition of phosgene, the reaction was purgedwith nitrogen gas, and the organic layer was extracted. The organicextract was washed once with dilute hydrochloric acid (HCl), andsubsequently washed with de-ionized water three times. The organic layerwas precipitated from methylene chloride into hot steam. The polymer wasdried in an oven at 110 deg C. before analysis. The Mw of thepolycarbonate was measured to be 47,428 g/mol (referenced topolycarbonate standards).

In similar manner branched polycarbonates were made using otherbranching levels, other end-capping agents and with various molecularweights. The experimental details for the polymers described herein arelisted in Table 1 below.

TABLE 1 Components PC-1 PC-2 PC-3 PC-4 PC-5 PC-6 PC-7 PC-8 PC-9Bisphenol A, g 4500 4500 4500 4500 4500 4500 4500 4500 4500 Endcap, gMHB, Ph, TBP, MP, PCP, Ph, Ph, TBP, TBP, 135 129.9 159.5 130 225 120.6168 251 177.6 Sodium gluconate, g 10 10 10 10 10 10 10 10 10Triethylamine, mL 42 42 42 42 42 42 42 42 42 Phosgene, g 2404 2405 25042506.3 2608 2407 2508 2404 2406 Tris(hydroxyphenyl)ethane, g 63 129.1 6464 167.4 128.5 196 196 126 Tris(hydroxyphenyl)ethane, 0.97 1.99 0.990.99 2.58 1.98 3.02 3.02 1.94 mol % Water, L 10 10 10.6 10.9 10.5 10 1010.6 10.2 Methylene chloride, L 23 23 24.3 24.6 24.4 23 23 24.4 24.5Molecular weight, g/mol 47428 37165 30283 29376 41680 41701 50299 5484350599

In Table 2 below the melt viscosity peak properties and the flameperformance (expressed both as p(FTP) values and actual UL94 testresults) for polymers PC-1 through PC-9 from Table 1 are listed. Thepeak melt viscosity values reported as “melt viscosity peak” in Table 2were obtained on dried polycarbonate powders while the p(FTP) and V0results were obtained on molded polycarbonate bars molded fromformulations containing the polycarbonate powders PC-1 to PC-9, aphosphite heat stabilizer (0.06 wt. %) and a hindered amine lightstabilizer (0.08 wt. %) and an FR package consisting of Rimar Salt,potassium perfluorobutane sulfonate (0.08 wt. %) andoctaphenylcyclotetrasiloxane (0.05 wt. %) based on the weight ofpolycarbonate of 100 wt. %.

TABLE 2 Properties PC-1 PC-2 PC-3 PC-4 PC-5 PC-6 PC-7 PC-8 PC-9 p (FTP)at 1.5 mm 0.93 0.99 0.93 0.88 0.96 0.97 0.99 0.99 0.99 p (FTP) at 1.2 mm— — — — 0.15 0.56 0.99 0.99 0 UL rating at 1.5 mm V0 V0 V0 V0 V0 V0 V0V0 — UL rating at 1.0 mm — — — — none none V0 V0 — Molecular weight,g/mol 47428 37165 30283 29376 41680 41701 50299 54843 50599 MeltViscosity Peak 18234 17712 8606 8159 20622 20705 27172 25692 20570(Poise) Melt Viscosity Peak - 20048 16490 7564 7081 21090 18910 2595925562 21683 Model (Poise)

Molded articles from PC-1 through PC-9 showed excellent V0 performanceat 1.5 mm A linear polycarbonate control having no branching and aphenol end-cap and having a MW value of 25,139 and Peak Melt Viscosityvalue of only 6,142 failed the UL 94 V0 test and was only rated V1 at1.5 mm.

Differentiation among the polycarbonates was observed when moldedarticles from PC-5 through PC-9 were tested at 1.0 mm PC-7 and PC-8failed V0 testing and with p(FTP) values well below 0.9 at 1.0 mm whilePC-8 and PC-9 passed at 1.0 mm with p(FTP) values at 0.99. PC-8 and PC-9had higher MWs (<47,000 vs. >55,000) and higher peak melt viscosities(<22,000 poise vs. >25,000 poise) than PC-7 and PC-8.

C1. Peak Melt Viscosity Predicting Equation

In order to help design polycarbonates that would consistently pass theUL 94 V0 test at thin wall thicknesses a predictive tool was needed.Based on the melt viscosity peaks (in poise) from 35 differentpolycarbonates (and 2 replicates) differing in MW, % branching agent andend-capping agent types differing in pKa value (p-cyanophenol,methyl-p-hydroxybenzoate, phenol, p-methoxyphenol, p-t-butylphenol, andp-cumylphenol) a polynomial equation that provided a model fit to thepeak melt viscosity data was obtained (Design-Expert® version 7.0.3 fromStat-Ease, Inc.). The parameters in the equation included the branchinglevel, BL (based on the total moles of branching agent/total moles ofthe bisphenol), the MW of the polycarbonate containing the end-cappingagent and branching agent (measured by GPC using polycarbonatestandards) and the pKa of the end-capping agent. The equation is shownbelow:Peak MeltViscosity=−57135.91+36961.39*BL+14001.13*MW^(1/3)−46944.24*pKa−322.51*BL*MW^(1/3)−2669.19*BL*pKa+215.83*MW^(1/3)*pKa+1125.63*BL²−200.11*MW^(2/3)+2231.15*pKa²*pKa values for all of the end-capping agents but p-t-butyl phenol andp-cumylphenol were obtained from the following reference: J. AM. CHEM.SOC. 2002, 6424. The values chosen in the reference were listed in theS7 category in Table 3 of the reference. The pKa value forp-t-butylphenol was obtained from the following reference: Journal ofMolecular Structure: THEOCHEM 805, 2006, 31. The pKa formethyl-p-hydroxybenzoate was obtained from the following reference:Chromatographia Vol. 39, No. 5/6, September 1994. The pKa value forp-cumylphenol was approximated based on the values of similarstructures.

The model characteristics are shown in Table 3 below:

TABLE 3 Model Characteristics R-Squared 0.87 Adjusted R-Squared 0.82Predicted R-Squared 0.70 Adequate Precision 14.34

The “Predicted R-Squared” of 0.70 is in reasonable agreement with the“Adjusted R-Squared” of 0.82. “Adequate Precision” measures the signalto noise ratio. A ratio greater than 4 is generally desirable. Here, theratio of 14.34 indicates an adequate signal and thus this model can beused to navigate the design space.

The pKa values used in the model for the end-capping agents are listedin Table 4 below:

TABLE 4 End-Capping Agent pKa* p-cyanophenol 8.2 p-methyl-hydroxybenzoate 8.4 phenol 9.9 p-t-butylphenol 10.2 p-methoxyphenol 10.4p-cumylphenol 10.5

The model then was used to recalculate the peak melt viscosity valuesidentified as Melt Viscosity Peak—Model (poise) in Table 2. Thecorrelations in general were excellent between the model and the actualPeak Viscosity values especially when the measured values exceeded20,000 poise. Above 20,000 poise the difference between the measured andcalculated melt viscosity values was consistently less than 10%

The calculated melt viscosity peak measurements were surprisinglyeffective at predicting the p(FTP) and V0 performance of polycarbonatesPC-5, PC-6, PC-7 and PC-8 at a thickness of 1.0 mm Polycarbonates havingPeak Melt Viscosity calculated values or measured below about 25,000poise failed the V0 test at 1.0 mm and had p(FTP) values below 0.9 asillustrated (PC-5 and PC-6) whereas polycarbonates having Peak MeltViscosity values measured or calculated values greater than about 25,000passed the V0 test at 1.0 mm and had p(FTP) values of 0.99 (PC-7 andPC-8).

D1. Blends with High Peak Viscosity Polycarbonates

Polycarbonates PC-10, PC-11 and PC-12 made with 3% THPE branching levelsand the end-capping agents phenol, methyl-p-hydroxybenzoate andp-cumylphenol respectively were prepared using the method describedabove. Based on the wt. % THPE levels, the pKas of the end-cappingagents and MWs of the polycarbonates, the calculated values from theequation above for the Peak Melt Viscosities were 22,960 (PC10), 25,683(PC-11) and 12,527 (PC12). Blend formulations with high flowpolycarbonate (made by an interfacial process and having p-cumylphenolend-capping agents with an average MW of 22,000 g/mol and an MVR of 25)were extruded with PC10, PC-11 and PC12. The blend formulations, MVRvalues of the resultant blends for and the flame properties of theblends are listed in Table 5 below.

TABLE 5 PMV MW (calculated) Components PC-10, wt. % 50 35526 22960PC-11, wt. % 50 41167 25683 PC-12, wt. % 50 31458 12527 High flow PC,wt. % 50 50 50 Octaphenyl- 0.5 0.5 0.5 cyclotetrasiloxane, wt. %* RimarSalt, wt. %* 0.8 0.8 0.8 Heat stabilizers, wt. %* 0.6 0.6 0.6 Moldrelease, wt. %* 0.27 0.27 0.27 Properties MVR (300, 1.2 kg, 360 s) 13.84.2 13.3 p(FTP) 0.97 0.99 0.2 (V0@1.5 mm/ 70° C. 168 Hr) p(FTP) 0 0 0(V0@1.0 mm/ 70° C. 168 Hr) UL 94 Rating @ 1.5 mm V0 V0 none *wt. % fromtotal amount of blended polycarbonate resins

The results from Table 5 illustrate the importance of making blendsusing a polycarbonate with a high peak melt viscosity value forapplications requiring thin wall flame properties. PC-10 and PC-12 havevery similar MWs (35,526 vs. 31,458 g/mol) and the blends compoundedfrom them have very similar MVRs (13.8 vs. 13.3) but the two blends werecompounded using polycarbonates (PC-10 and PC-12) having very differentcalculated Peak Melt Viscosities (22,960 vs. 12,527). This differenceappears to result in a very different flame performance for the twoblends, one passing the UL 94 V0 test at 1.5 mm (from PC-10 having ahigh calculated Peak Melt Viscosity of 22,960 and the other blend PC-12failing UL 94 V0 testing at 1.5 mm from PC-12, having a low calculatedPeak Melt Viscosity of 12,527).

While typical embodiments have been set forth for the purpose ofillustration, the foregoing descriptions should not be deemed to be alimitation on the scope herein. Accordingly, various modifications,adaptations, and alternatives can occur to one skilled in the artwithout departing from the spirit and scope herein.

We claim:
 1. A composition comprising: a polycarbonate of the followingformula

wherein at least 60 percent of the total number of R¹ groups containaromatic groups and the balance thereof are aliphatic or alicyclicgroups; wherein the polycarbonate was formed in the presence of anend-capping agent and the end-capping agent is not cyanophenol; whereinthe polycarbonate has a branching level of at least about 2%; whereinthe polycarbonate has a weight average molecular weight of between about20,000 g/mole to 54,843 g/mole as measured by gel permeationchromatography using polycarbonate standards; and wherein thepolycarbonate has a peak melt viscosity of at least 25,000 poise whenmeasured using a parallel plate melt rheology test at a heating rate of10° C./min at a temperature of between about 350° C. to about 450° C. ata frequency of 3 rad/s and strain amplitude of 9%; and a flameretardant; and a thermoplastic polymer that is different than thepolycarbonate; wherein a molded article of the polycarbonate and theflame retardant has a UL94 V0 rating at a thickness of 1.0 mm; andwherein a molded article of the composition has a UL94 V0 rating at athickness of 1.5 mm.
 2. The composition of claim 1, wherein thepolycarbonate has a weight average molecular weight of between about20,000 g/mole to about 40,000 g/mole as measured by gel permeationchromatography using polycarbonate standards.
 3. The composition ofclaim 1, wherein the end-capping agent has a pKa between about 8.3 andabout
 11. 4. The composition of claim 1, wherein the end-capping agentis selected from at least one of the following: a phenol and a phenolcontaining one or more substitutions with at least one of the following:an aliphatic group, an olefinic group, an aromatic group, a halogen, anester group, and an ether group.
 5. The composition of claim 1, whereinthe end-capping agent is selected from at least one of the following:phenol, p-t-butylphenol, and p-cumylphenol.
 6. The composition of claim1, wherein the polycarbonate of said composition has a branching levelof at least about 3%.
 7. The composition of claim 1, wherein the flameretardant comprises at least one of the following: alkali metal salts ofperfluorinated C₁₋₁₆ alkyl sulfonates; potassium perfluorobutanesulfonate; potassium perfluoroctane sulfonate; tetraethylammoniumperfluorohexane sulfonate; and potassium diphenylsulfone sulfonate. 8.The composition of claim 1, wherein the thermoplastic polymer is asecond polycarbonate comprising a repeating structure of

wherein the second polycarbonate is different from said polycarbonate,and wherein at least 60 percent of the total number of R¹ groups containaromatic groups and the balance thereof are aliphatic or alicyclicgroups; and wherein at least a portion of the R¹ groups are derived frombisphenol-A.
 9. The composition of claim 1, wherein the composition hasa haze value of less than 1.5% at 3.2 mm thickness by ASTM D1003. 10.The composition of claim 1, wherein the polycarbonate is derived frombisphenol-A.
 11. The composition of claim 1, wherein the thermoplasticpolymer is a second polycarbonate derived from bisphenol-A.
 12. Thecomposition of claim 1, wherein the polycarbonate is selected from atleast one of the following: a homopolycarbonate derived from abisphenol; a copolycarbonate derived from more than one bisphenol; and acopolymer derived from one or more bisphenols and comprising one or morealiphatic ester units, aromatic ester units, and siloxane units.
 13. Thecomposition of claim 1, wherein the thermoplastic polymer comprises atleast one of polyester, polyamide, polysiloxane, polycarbonate, and acopolymer comprising at least one of the foregoing.
 14. The compositionof claim 1, wherein the thermoplastic polymer is a polycarbonatecopolymer selected from polycarbonate-polysiloxane copolymers, andpolyester-polycarbonates.
 15. The composition of claim 1, wherein thethermoplastic polymer comprises copolycarbonate-polyester-polysiloxaneterpolymer.
 16. An article comprising the composition of claim
 1. 17. Acomposition comprising: a first polycarbonate of the following formula

wherein at least 60 percent of the total number of R¹ groups containaromatic groups and the balance thereof are aliphatic or alicyclicgroups; wherein the first polycarbonate was formed in the presence of anend-capping agent and the end-capping agent is not cyanophenol; whereinthe first polycarbonate has a branching level of at least about 2%;wherein the first polycarbonate has a weight average molecular weight of20,000 g/mole to 54,843 g/mole as measured by gel permeationchromatography using polycarbonate standards; and wherein the firstpolycarbonate has a peak melt viscosity of at least 8,000 poise whenmeasured using a parallel plate melt rheology test at a heating rate of10° C./min at a temperature of between about 350° C. to about 450° C. ata frequency of 3 rad/s and strain amplitude of 9%; and a flameretardant; and a second polycarbonate derived from at least bisphenol-A,wherein the second polycarbonate is different from the firstpolycarbonate; wherein a molded article of the polycarbonate and theflame retardant has a UL94 V0 rating at a thickness of 1.0 mm; andwherein a molded article of the composition has a UL94 V0 rating at athickness of 1.5 mm.
 18. The composition of claim 17, wherein the peakmelt viscosity is at least 22,960 poise.
 19. The composition of claim17, wherein the first polycarbonate of said composition has a branchinglevel of at least about 3%.